i did this on the xbox
im not sure if this has been found yet.
in the level delta halo, get a carbine from an elite by the first structure (keep the rocket launcher too). get in the warthog that gets dropped off. drive to the next structure and kill all the covenant without letting anything get into either 2 ghosts in front of the building. shoot the right gun on the ghost closest to the ramp with the carbine about 4 or 5 times. go in between the 2 ghosts so that your back is facing the wall and melee the ghost on your right with the rocket launcher so that it moves. keep doing this until it explodes and then another ghost will spawn right next to you.
