Shield door
From Halopedia, the Halo wiki
Shield Doors are Covenant[1] and Forerunner[2] created doors that allow people through while repelling plasma, gunfire, vehicles and virtually any other objects. They are similar in design to Bubble Shields with differences being the color and infinite usage time. The Shield Door is similar to Anti-Vehicle Barriers.
There are several in past Halo games and they appear in Halo 3 on the multiplayer maps Epitaph and Snowbound.
They are also featured as forge items in the Heroic, Legendary and Mythic map packs. They can be placed in almost any door as well as anywhere else the Forge user desires.
If one stands exactly in the shield door's energy field, doing a melee or shooting in any direction will be negated by the shield. However, the player is still vulnerable from attacks from either side. This also works with the Bubble Shield. By overloading a map with shield doors (Using excessive Trip Mines to cause the map to lose control of the maps graphical and geometrical assets), the shield doors on a map will disappear.
Trivia
- Despite the fact that shield doors protect from projectiles, plasma and vehicles, explosions can still affect players and objects on the other side of them. A perfect example of this is the underground shield on Snowbound, where the nearby power coils can be detonated to instantly kill players standing on the other side. It is unknown if this is a glitch or Bungie meant to do this.
- In the secondary versions of the maps Snowbound and Epitaph, namely Boundless and Epilogue, the map Shield Doors are removed.