okay, in the level The Covenant, the time you have to kill the 2 scarabs, simply go down with a ghost or warthog (dont take the hornets) and drive to the left side of the citadel where you can fall and die, if you keep driving and fell to the end of the cliff with your warthog or ghost, you will not die and just stay there, TRY IT OUT! ITS FUN! this is not bul****, and i the first person to get this glitch.

PS: DO NOT FIGHT THE SCARABS, JUST IGNORE THEM AND KEEP DRIVING AS FAST AS YOU CAN.