Gravemind (Level): Difference between revisions
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==Walkthrough== | ==Walkthrough== | ||
===01: Inside Job=== | |||
Well, this is about as bad a situation as you could possibly be in. You have two Brutes to kill, and a Needler to do it with. | |||
... | |||
The phrase, "Oh crap," comes to mind. | |||
Well, I guess we have to make the best of a bad deal. Don't unload the needler into the Brutes. The new needler fires so quickly that you only need to hold down the triggers for about a second and a half before you've got seven needles in the air. And seven needles are all it takes to kill something. In this case, a Brute. Don't fire unless you're running forward, and certainly don't fire when the Brutes are near cover—it is a waste of ammo, as they will dodge. And ammo is pretty scarce here. Still, these Brutes shouldn't take too long—they're in an even worse position than you. | |||
Once you kill one, the other turns into an Insane Space Gorhino and starts a quest to bludgeon you to death. Yeah, thanks for warning us, Cortana. However, in my opinion, berserkers are easier to kill than normal Brutes. They aren't shooting you, they have no concept of cover or even dodging, and they don't seem to realize that they can't reach you when you are standing on a pillar five feet tall. This is, in fact, a pretty good strategy. Jump up on the pillar, let him get close, then kill him. If you are particularly leet, you will use the needler blast to jump up into the Council Chamber's seats. The seats make a very good platform for this fight, incidentally. So you're going to jump up there anyway, but not quite yet. | |||
The seats are a good place to shoot from—high ground, as it were. They even have little alcoves in which you can take cover. Your main problem will be conserving ammo, as all the guns are on the floor, and the floor is not where you want to be. However, there is a simple way to get ammo without being harassed by the Brutes. A new wave of enemies does not spawn until every member of the previous wave is killed. Just leave one Grunt alive, and you can gather whatever supplies you need before killing him and scampering back to cover. | |||
After you've killed the Brutes, the four Grunts show back up. Grab the two Brute Plasma Rifles. Kill three, stock up on needles, kill the fourth, drop a rifle, switch to the needler, grab the other needler, and get up into the seating by jumping from one of the pillars. Yay, checkpoint. You'll need it. The doors will open up. As soon as one does, pour some needles in there. There are four Grunts and two Brutes in this wave. With luck, one (or even two) of these have Carbines. Kill the Brutes, leave one Grunt alive, stock up on ammo, grab a Carbine instead of your plasma rifle, and dual-wield needlers again. Trigger the next wave. | |||
This one is pretty tricky. Only the four Grunts come out of the doors this time. Three Brutes, one of which carries a Brute Shot, come up the elevator that the Prophets left on. This makes them much harder to kill. Luckily, with your flanking position and the relative lack of cover on the elevator, should be able to kill the Brute Captain and possibly the Major with your needlers before the Minor takes cover. Since you have the carbine, however, whip it out and get a headshot on him and it's sayonara to them. The four Grunts won't be much trouble; again, however, hold off triggering the next wave until you're full up on ammo. Hopefully, by now, you'll be full on plasma grenades, too. This time, unfortunately, the next wave spawns when only two enemies are left, and it's two carbine Brutes, coming from the seats. If you are lucky, they will both be on the other side; if not, they will both be on your side. Usually, though, there's one on each side. Kill the nearest first; use the carbine. This is the most dangerous part of the fight, partly because the Grunts sometimes lob grenades to distract you. | |||
Once you're done, head for the doors, filling up on ammo as you go. | |||
Six Grunts and two Brutes await you in the next room. Four of the Grunts are near you; a grenade and some carbining will settle their hash. Two of the Grunts are further up, manning turrets, and you'll have to needle them from your current position. The Brutes here can be tricky; it's hard to headshot a berserk Brute on this uneven surface, and there are too many walls for needles to hit. I suggest applying a plasma grenade. | |||
Once they're all dead, open the door. Two Honor Guard Brutes are waiting for you. With luck, you can dual-needler both of them to death before they hurt you too much. Two more Brutes and two Jackals are about halfway down this area; you can carbine-snipe them for best results. However, when only two enemies are left, another wave comes up from the grav-lift: two turret-Grunts, two normal Grunts and three Brutes, one of which has a Brute Shot. It's best to target the turret-Grunts before they can set up their turrets. Then let the Brutes come up and fill them full of needles. It should be noted that, unlike those before them, these Brutes will lob grenades practically non-stop. Still, you have a lot of distance to work over, so these guys shouldn't be too difficult. | |||
When they're all dead, draw your carbine and walk backwards into the grav-lift. Why backwards? Because two Jackals (one a sniper) and two Grunts will come to greet you. With the carbine, you can kill them all before you hit the ground. Finish them and open the door. If you wait a second, a Jackals will head by at top speed. Slow it down a little with your carbine. It's wonderfully amusing to watch it do a faceplant as it dies. Then, head left, and a minor Jackal and a minor Brute will show up from the end of the hall. A couple of headshots will end their miserable lives for them. A major Jackal will follow them, but he should die just as quickly. Jump onto the raised path to the left and grab another needler from the crate. You still have two Brutes, a Jackal and three Grunts to deal with, but dual needlers should make them much less dangerous and much less alive. Beware of the berserking Brute: it's hard to dodge backwards in this type of hall, and there isn't much space that it can't follow you to. Just stick to your needlers, and you should be okay. | |||
In the next room, two Jackals will show up on the right, but they should be easy to carbine. The next room is pretty hard. You have six Grunts to deal with—not to mention four Brutes. Your objective should be to move through this room as fast as possible. If you are too slow, a fifth Brute may come through the door at the end of the hall. | |||
The big area with the grav-lift. Ah, how I hate this part. When you enter, there will be a Jackal on either side of you and three Brutes on the lower level. Quickly carbine the two Jackals, then move forward and wait for two of the Brutes to come up via the grav-lift. As they do, they'll face away from you for some odd reason. Perfect opportunity to stick them with grenades. If you're stealthy enough, you could even assassinate them, although getting that close is not recommended. | |||
Move quickly around the perimeter of the room. As you approach, each of the three doors will open, revealing a Brute with a Grunt behind it. Kill them all, one at a time. The one Brute remaining, on the bottom level, will go berserk, but since he doesn't know where you are, he should be easy bait for a plasma nade. Then again, he sometimes runs into the gravlift and sees you, which can make your task a bit tricky. To escape him, jump on top of a weapons crate and hop up to one of the little ledges. From there, you can target him unpestered. | |||
Once all eleven enemies are dead, crouch-walk into the gravity lift. Stay crouched all the way down, and you are more likely to survive the detention block. | |||
I have had mixed results with the detention block. Sometimes, the enemies seem to know that you're coming; they'll shoot at you from the second you're visible. This usually results in being dead before you hit the ground. However, sometimes they don't have the slightest idea you're there, and you can kill them all without firing a shot. Go figure. Assuming they don't see you, here's what to do: | |||
Melee the two Brutes in the back. One will berserk, but since they can't see you, you should be able to assassinate it easily. Drop your needler in exchange for a Brute Shot. You won't be firing it much, but its swift and deadly melee is invaluable here. | |||
The Covenant appear to be pretty lax about their security forces. All the Grunts are asleep. However, there is a patrolling Jackal, who will be glad to wake them all up. Wait until its back is to you before whacking it in two from behind with the Shot's bayonet. There are five Grunts asleep here; kill them all, then head over to the lifts. Wait, and watch your motion tracker; a Jackal major will start patrolling on the lower level. Wait until he's headed away from you, then drop down the lift, run up, and break his spine. There is also a sleeping Grunt here; take it out now so you don't have to worry about it later. Head back over to the lifts. Again, watch your motion tracker; there's another Jackal. Give him the same treatment as his pal upstairs. | |||
If you're spotted on the way down, I can't help you much; you're in for a tense, paranoid and hard journey down. I'd suggest just reloading to checkpoint and hoping you have better luck this time. | |||
Having cleared out the levels, you will get a message from Cortana, saying that she's located Marines on either the middle or lower level. Two Brutes and three Jackals will appear on the level she specifies, and this time they'll know where you are. I suggest heading a level above them and sniping them with the Carbine from afar. Once they're all dead, head into the cells. On the middle level, the cell is to the left of the lifts; inside are two Jackals with their backs to you and a Brute facing you. On the lower level, the door is right of the lifts; inside there are four sleeping Grunts and a Brute with its back to you. Neither one should pose a challenge to you, with your Brute Shot and Carbine. | |||
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[[Category:Halo 2 Campaign]] | [[Category:Halo 2 Campaign]] |
Revision as of 16:05, April 3, 2007
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Gravemind | |
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Inside High Charity |
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Halopedia has a walkthrough guide for this level; see Gravemind (Level)/Walkthrough. |
Gravemind is a Halo 2 campaign level. The Gravemind teleports the Master Chief to High Charity. The Prophet of Truth has the Index, and you must get to him before he leaves. As you you travel through High Charity, the Covenant begin their civil war. You will move through battles between the Elites, Grunts, and Hunters versus the Brutes, Jackals and Drones.
Strangely enough, apart from the opening cutscene, there is no contact with the titular character or his Flood minions. Also of note, is that the word "Gravemind" is not mentioned until two levels later in High Charity. This is also the level where the Energy Sword appears very often.
This is the first level in which Brutes are combatted.
In this level you will not be able to use any human weapons.
Summary
Council Chamber -> place where pre-Arbiter was tortured (name?) -> weird hallways (name?) -> grav lift room (name?) -> Holding Chambers -> grav lift room (name?) -> weird hallways (name?) -> Hanging Garden A (is that right?) -> big hallway thing (name?) -> lightbridge (name?) Valley of Tears A (is that right?) -> lightbridge (name?) -> small tower (name?) -> lightbridge (name?) -> Valley of Tears B (is that right?) -> lightbridge (name?) -> big hallway thing (name?) -> Hanging Garden B (is that right?) -> weird hallways (name?) -> grav lift room (name?) -> bridge (name?) -> Mausoleum of the Arbiter -> bridge (name?)
Weapons
- Plasma Pistol
- Plasma Rifle
- Brute Plasma Rifle
- Needler
- Carbine
- Fuel Rod Cannon
- Brute Shot
- Energy Sword
- Shielded Plasma Cannon
- Plasma Cannon
Transcript
Chapter 1: Inside Job
{Master Chief begins to wake up, we see a red circle of lights on the ceiling of some underground area. We see that he's being held by a tentacle and brought towards a massive creature (Gravemind).}
Cortana: "What... is that?"
{The Chief is held in front of Gravemind's head. The head being one giant mouth made from separate parts, similar to an Elite's}
Gravemind: "I? I am a monument to all your sins."
{As Gravemind talks, he breathes out vapors found in Flood infestations. Two tentacles bring a struggling Arbiter.}
Master Chief: "Relax. I'd rather not piss this thing off."
Arbiter: "Demon!"
{the Gravemind makes loud huffing sounds, indicates the Chief}
Gravemind: "This one is machine and nerve, and has its mind concluded." {a tentacle wraps around Master Chief's head, then indicates the Arbiter} "This one is but flesh and faith, and is the more deluded."{turns the Arbiter upside down}
Arbiter: "Kill me or release me, parasite. But do not waste my time with talk!"
Gravemind: "There is much talk. And I have listened. Through rock, and metal, and time. Now I shall talk, and you shall listen."
{he raises two tentacles, one wrapped around a red Monitor, the other merged with a half-Flood Prophet of Regret}
Monitor: "Greetings. I am 2401 Penitent Tangent. I am the Monitor of Installation 05."
Prophet of Regret: "And I am the Prophet of Regret, Councilor most high, Hierarch of the Covenant!"
2401 Penitent Tangent: "A Reclaimer? Here? At last. We have much to do. This facility must be activated if we are to control this outbreak."
Prophet of Regret: "Stay where you are! Nothing can be done until my sermon is complete!"
2401 Penitent Tangent: "Not true. This installation has a successful utilization record of 1.2 trillion simulated and one actual. It is ready to fire on demand."
Prophet of Regret: "Of all the objects our Lords left behind, there are none so worthless as these Oracles! They know nothing of the Great Journey!"
2401 Penitent Tangent: "And you know nothing about containment! You have demonstrated a complete disregard to even the most basic protocols!"
Gravemind: "This one's containment..." {gives a disgusted huff} "And this one's 'Great Journey' are the same." {he lowers the tentacles, Regret shrieks in fear} "Your Prophets have promised you freedom from a doomed existence, but you will find no salvation on this ring. Those who built this place knew what they wrought. Do not mistake their intent, or all will perish as they did before..."
Master Chief: "This thing is right. Halo is a weapon. Your Prophets are making a big mistake."
Arbiter: "Your ignorance already destroyed one of the sacred rings, demon. It shall not harm another."
Gravemind: "If you will not hear the truth, then I will show it to you. There is still time to stop the key from turning, but first it must be found." {indicates each in turn} "You will search one likely spot, and you will search another. Fate had us meet as foes, but this ring will make us brothers!"
{MC and the Arbiter disappear in teleportation rings. Fade to black, fade in on High Charity.}
{A swarm of Covenant ships attack each other. Fade in on the walkway outside the Council Chamber, Honor Guard Brutes guard the gates from rioters.}
Prophet of Truth (voice over): "We are all of us, gravely concerned."
{Cut to Council Chamber. A line of Honor Guard Brutes stand at attention. A cameraman Grunt focuses a holographic camera on Truth as he delivers his propaganda, while the Prophet of Mercy watches from aside.}
Prophet of Truth: "The release of the parasite was unexpected, unfortunate. But, there is no need to panic. In truth, this is a time to rejoice. A moment that all the Covenant should savor." {raises the Index} "For the Sacred Icon has been found. With it, our path is clear, our entry into the Divine Beyond guaranteed! The Great Journey is nigh..." {the Grunt notices the Chief teleporting in behind him} "...and nothing, not even the Flood, can stop it."
Master Chief: "Boo."
{the Grunt yelps, throws up his needler and runs, the Chief catches the needler, aims it at the Prophets. Two Brute Honor Guards shield Truth with their Honor Pikes.}
Prophet of Truth: "Kill the demon!"
{the Prophets and some Brutes escape through a gravlift, leaving two Brutes}
Gameplay
Cortana: "Brutes! The faster you can kill these Brutes, the better." {MC kills one Brute} "They don't have shield generators, but take them out before... it's berserking!"
{MC kills all Covenant in the room}
Tartarus (loudspeaker): "The demon has entered the Council chamber?! Protect the Hierarchs! Seal the exits."
Cortana: "Oh, I don't think so. Put me down on one of the pedestals near the door."
{MC does so, Cortana's hologram appears}
Cortana: "That Prophet... Truth, he has the Index. You've got to take it from him. Let me get these doors. Go! It will be easier to track Truth if I stay in the network. Don't worry. You can pick me up later."
{MC fights his way to the ledge where the Arbiter was tortured}
Cortana: "Watch out for the Captain, it's got a Brute Shot!"
Cortana: "Truth is moving through the lower levels of the tower. I'll reverse this gravlift. Drop down, try to cut him off." {if MC pauses} "It's safe, really. Just step in."
{If you continue to stall}
Cortana: "After that stunt on the Cairo, I know you're not afraid of heights."
Cortana: "Fine, I won't watch. Meet you at the bottom, okay?"
{later}
Tartarus (loudspeaker): "Reinforce all approaches to the holding pens. Slay the demon on sight!"
Cortana: "They're beefing up their patrols. Stay sharp."
{later}
Cortana: "Wait a minute! I'm reading marine IFF transponders. The signals are originating somewhere below your position."
Cortana: "There's another lift in the next room."
{MC takes a gravlift down}
Cortana: "There are two groups of marines in this detention block. I'll zero their locations. You neutralize the guards. ...Quietly."
{MC frees the marines}
Cortana: "Listen up, marines! The Chief's hunting a Prophet, and you're gonna help him kill it."
Marine: "Affirmative!"
or
Marine: No waste sticking around here!
Cortana: "That's all the marines, Chief. Good work. We'll get out of here the same way we came in--the central gravlift. ...Hostile reinforcements coming down the lift!"
{MC kills the reinforcements}
Cortana: "The lift is clear. Step on in."
{later}
Prophet of Truth (loudspeaker): "Fear not, my brothers! The Sacred Icon is secure. It was Tartarus and his Brutes who took the Icon from the Flood, and for that they have our thanks."
Cortana: "Excellent! Truth is broadcasting on the move. It'll make him much easier to track."
{later}
Prophet of Truth (loudspeaker): "The Elites have failed to protect the Prophets, and in doing so, have put all our lives at risk. Let no warrior forget his oath, 'Thou, in faith, shall keep us safe, whilst we find the Path.'"
Cortana: "I've got a fix on Truth, just outside this tower, Chief. There's an exit nearby. Hurry."
{later}
Prophet of Truth (loudspeaker): "With my blessing, the Brutes now lead our fleets! They ask for your allegiance, and you shall give it."
Cortana: "You wouldn't believe the number of kill-systems the Covenant are throwing down around me. Not to worry, it's pretty sloppy stuff. I guess they never expected a hostile intelligence to penetrate their networks from the inside."
{later}
Cortana: "The Covenant just destroyed two of their own ships. And I'm hearing reports of small arms fire throughout their fleet."
Prophet of Truth (loudspeaker): "Creatures of the Covenant! The path is broad, and we shall walk it side by side."
{later}
Cortana: "Slipspace rupture. It's In Amber Clad!" {In Amber Clad flies by overhead} "Hailing... No response. She's crashed into another tower ahead of our position. I'll keep trying to make contact, but I'm not registering any human vital signs."
Prophet of Truth (loudspeaker): "Be Glad! A reward for all your toil and all your sacrifices in the year at hand."
{later}
Prophet of Truth (loudspeaker): "At this moment, the Council is gathered on Halo, to see the Icon safely placed."
Tartarus (loudspeaker): "Rise, my brothers! Cast down the Elites!"
Prophet of Truth (loudspeaker): "There are those who said this day would never come. What have they to say now?"
Tartarus (loudspeaker): "Once the towers are clear, we'll drive them from the lower district."
{later}
Prophet of Truth (loudspeaker): "I have listened to the Oracle, and confirmed our deepest hope. The Great Journey begins with Halo."
Tartarus (loudspeaker): "The Elites are falling back to the Mausoleum. Fools! Their Arbiter can do nothing for them now."
Prophet of Truth (loudspeaker): "Who would doubt the Prophets? What have they foretold that has not come to pass?"
{later}
Cortana: "If we're going to catch Truth, we'll need to take a shortcut, straight through the Mausoleum. Look on the bright side, for now, they seem much more interested in killing each other."
{MC approaches the large fight in the Mausoleum}
Cortana: "You might consider sitting this one out."
{Once the battle begins, where you watch Brute Captains and Ultra Elites duke it out, you'll hear the instrumental version of Breaking Benjamin's "Blow Me Away"}
{after the room is cleared}
Cortana: "Hang on! I'm picking up two more transponders. It's the Commander and Johnson! They're closing on Truth's position, Chief. They'll need your help. This way, Chief. ...This isn't good. I’m getting confirmed reports of Flood leaving In Amber Clad's wreckage. Let's get the Index and find a way out of here. Before things get really ugly."
Second Cinematic
{Tartartus and his Brutes take Keyes, Johnson and 343GS toward a platform where the Prophets of Truth and Mercy wait with three Phantoms}
Tartarus: "Split them up. One in each Phantom."
{Three Brutes do so, two Phantoms take off. Tartarus kneels before the Prophets.}
Prophet of Truth: "The hopes of all the Covenant rest on your shoulders, Chieftain."
{Truth hands Tartarus the Index}
Tartarus: "My faith is strong. I will not fail."
{Infection Forms spring up and rush them. The Brutes get ready. They manage to crush most of them, but one gets through and knocks Mercy off his throne}
Prophet of Mercy: "Ahhh! Ahhh!"
{Tartarus moves to kill the Flood}
Prophet of Truth: "Let him be. The Great Journey waits for no one, brother. Not even you."
{Truth boards the Phantom, the Honor Guard Brutes follow immediately, but Tartarus pauses at dying Mercy. He looks at the Index and turns away from Mercy.}
Walkthrough
01: Inside Job
Well, this is about as bad a situation as you could possibly be in. You have two Brutes to kill, and a Needler to do it with.
...
The phrase, "Oh crap," comes to mind.
Well, I guess we have to make the best of a bad deal. Don't unload the needler into the Brutes. The new needler fires so quickly that you only need to hold down the triggers for about a second and a half before you've got seven needles in the air. And seven needles are all it takes to kill something. In this case, a Brute. Don't fire unless you're running forward, and certainly don't fire when the Brutes are near cover—it is a waste of ammo, as they will dodge. And ammo is pretty scarce here. Still, these Brutes shouldn't take too long—they're in an even worse position than you.
Once you kill one, the other turns into an Insane Space Gorhino and starts a quest to bludgeon you to death. Yeah, thanks for warning us, Cortana. However, in my opinion, berserkers are easier to kill than normal Brutes. They aren't shooting you, they have no concept of cover or even dodging, and they don't seem to realize that they can't reach you when you are standing on a pillar five feet tall. This is, in fact, a pretty good strategy. Jump up on the pillar, let him get close, then kill him. If you are particularly leet, you will use the needler blast to jump up into the Council Chamber's seats. The seats make a very good platform for this fight, incidentally. So you're going to jump up there anyway, but not quite yet.
The seats are a good place to shoot from—high ground, as it were. They even have little alcoves in which you can take cover. Your main problem will be conserving ammo, as all the guns are on the floor, and the floor is not where you want to be. However, there is a simple way to get ammo without being harassed by the Brutes. A new wave of enemies does not spawn until every member of the previous wave is killed. Just leave one Grunt alive, and you can gather whatever supplies you need before killing him and scampering back to cover.
After you've killed the Brutes, the four Grunts show back up. Grab the two Brute Plasma Rifles. Kill three, stock up on needles, kill the fourth, drop a rifle, switch to the needler, grab the other needler, and get up into the seating by jumping from one of the pillars. Yay, checkpoint. You'll need it. The doors will open up. As soon as one does, pour some needles in there. There are four Grunts and two Brutes in this wave. With luck, one (or even two) of these have Carbines. Kill the Brutes, leave one Grunt alive, stock up on ammo, grab a Carbine instead of your plasma rifle, and dual-wield needlers again. Trigger the next wave.
This one is pretty tricky. Only the four Grunts come out of the doors this time. Three Brutes, one of which carries a Brute Shot, come up the elevator that the Prophets left on. This makes them much harder to kill. Luckily, with your flanking position and the relative lack of cover on the elevator, should be able to kill the Brute Captain and possibly the Major with your needlers before the Minor takes cover. Since you have the carbine, however, whip it out and get a headshot on him and it's sayonara to them. The four Grunts won't be much trouble; again, however, hold off triggering the next wave until you're full up on ammo. Hopefully, by now, you'll be full on plasma grenades, too. This time, unfortunately, the next wave spawns when only two enemies are left, and it's two carbine Brutes, coming from the seats. If you are lucky, they will both be on the other side; if not, they will both be on your side. Usually, though, there's one on each side. Kill the nearest first; use the carbine. This is the most dangerous part of the fight, partly because the Grunts sometimes lob grenades to distract you.
Once you're done, head for the doors, filling up on ammo as you go.
Six Grunts and two Brutes await you in the next room. Four of the Grunts are near you; a grenade and some carbining will settle their hash. Two of the Grunts are further up, manning turrets, and you'll have to needle them from your current position. The Brutes here can be tricky; it's hard to headshot a berserk Brute on this uneven surface, and there are too many walls for needles to hit. I suggest applying a plasma grenade.
Once they're all dead, open the door. Two Honor Guard Brutes are waiting for you. With luck, you can dual-needler both of them to death before they hurt you too much. Two more Brutes and two Jackals are about halfway down this area; you can carbine-snipe them for best results. However, when only two enemies are left, another wave comes up from the grav-lift: two turret-Grunts, two normal Grunts and three Brutes, one of which has a Brute Shot. It's best to target the turret-Grunts before they can set up their turrets. Then let the Brutes come up and fill them full of needles. It should be noted that, unlike those before them, these Brutes will lob grenades practically non-stop. Still, you have a lot of distance to work over, so these guys shouldn't be too difficult.
When they're all dead, draw your carbine and walk backwards into the grav-lift. Why backwards? Because two Jackals (one a sniper) and two Grunts will come to greet you. With the carbine, you can kill them all before you hit the ground. Finish them and open the door. If you wait a second, a Jackals will head by at top speed. Slow it down a little with your carbine. It's wonderfully amusing to watch it do a faceplant as it dies. Then, head left, and a minor Jackal and a minor Brute will show up from the end of the hall. A couple of headshots will end their miserable lives for them. A major Jackal will follow them, but he should die just as quickly. Jump onto the raised path to the left and grab another needler from the crate. You still have two Brutes, a Jackal and three Grunts to deal with, but dual needlers should make them much less dangerous and much less alive. Beware of the berserking Brute: it's hard to dodge backwards in this type of hall, and there isn't much space that it can't follow you to. Just stick to your needlers, and you should be okay.
In the next room, two Jackals will show up on the right, but they should be easy to carbine. The next room is pretty hard. You have six Grunts to deal with—not to mention four Brutes. Your objective should be to move through this room as fast as possible. If you are too slow, a fifth Brute may come through the door at the end of the hall.
The big area with the grav-lift. Ah, how I hate this part. When you enter, there will be a Jackal on either side of you and three Brutes on the lower level. Quickly carbine the two Jackals, then move forward and wait for two of the Brutes to come up via the grav-lift. As they do, they'll face away from you for some odd reason. Perfect opportunity to stick them with grenades. If you're stealthy enough, you could even assassinate them, although getting that close is not recommended.
Move quickly around the perimeter of the room. As you approach, each of the three doors will open, revealing a Brute with a Grunt behind it. Kill them all, one at a time. The one Brute remaining, on the bottom level, will go berserk, but since he doesn't know where you are, he should be easy bait for a plasma nade. Then again, he sometimes runs into the gravlift and sees you, which can make your task a bit tricky. To escape him, jump on top of a weapons crate and hop up to one of the little ledges. From there, you can target him unpestered.
Once all eleven enemies are dead, crouch-walk into the gravity lift. Stay crouched all the way down, and you are more likely to survive the detention block.
I have had mixed results with the detention block. Sometimes, the enemies seem to know that you're coming; they'll shoot at you from the second you're visible. This usually results in being dead before you hit the ground. However, sometimes they don't have the slightest idea you're there, and you can kill them all without firing a shot. Go figure. Assuming they don't see you, here's what to do:
Melee the two Brutes in the back. One will berserk, but since they can't see you, you should be able to assassinate it easily. Drop your needler in exchange for a Brute Shot. You won't be firing it much, but its swift and deadly melee is invaluable here.
The Covenant appear to be pretty lax about their security forces. All the Grunts are asleep. However, there is a patrolling Jackal, who will be glad to wake them all up. Wait until its back is to you before whacking it in two from behind with the Shot's bayonet. There are five Grunts asleep here; kill them all, then head over to the lifts. Wait, and watch your motion tracker; a Jackal major will start patrolling on the lower level. Wait until he's headed away from you, then drop down the lift, run up, and break his spine. There is also a sleeping Grunt here; take it out now so you don't have to worry about it later. Head back over to the lifts. Again, watch your motion tracker; there's another Jackal. Give him the same treatment as his pal upstairs.
If you're spotted on the way down, I can't help you much; you're in for a tense, paranoid and hard journey down. I'd suggest just reloading to checkpoint and hoping you have better luck this time.
Having cleared out the levels, you will get a message from Cortana, saying that she's located Marines on either the middle or lower level. Two Brutes and three Jackals will appear on the level she specifies, and this time they'll know where you are. I suggest heading a level above them and sniping them with the Carbine from afar. Once they're all dead, head into the cells. On the middle level, the cell is to the left of the lifts; inside are two Jackals with their backs to you and a Brute facing you. On the lower level, the door is right of the lifts; inside there are four sleeping Grunts and a Brute with its back to you. Neither one should pose a challenge to you, with your Brute Shot and Carbine.