Battle Rifle-Plasma Rifle
From Halopedia, the Halo wiki
During the cutscene Uncomfortable Silence where the Arbiter is attacked by an Enforcer and is saved by a Phantom, the Phantom never really shoots. Instead there is a combined weapon that shoots the Enforcer, as seen in this image. You cannot see it in the cutscene; it can only be viewed when you pause the game and move the camera angle as shown in the below video link:
Paused Uncomfortable Silence Cutscene file
Why
If you look closely at the phantom, both after and before the attack, you'll see that it has no cannons on it. If the phantom where to shoot the Enforcer by it self, it wouldn't stop shooting until the Enforcer was down, which ment that it would fire, and fire, until it dissapears in the mist. Now, when it has no guns and the BR-PR appears, it will only fire for a brief moment.
