MAC gun glitch

On the "Return to Sender" part of Cairo Station there is a metal object moving back and forth. If you watch it lookes like when it moves back a bomb is loaded into it, then when it moves forward it drops the bomb into another hole. It is thought to be the mac gun ammo. Get in the way of the "metal object;" when it comes forward you will be dropped down the hole. You will die, but you get to see the room that master chief send the bomb out of when he opens the door in the cinematic.

Also, you can get stuck in the mac gun barrel. My friend got shot out of the cannon into space!!! Just stand in front of the reloading thingy and it should push you into the barrel. You will then die and get shot out into space. An elite sometimes get stuck in it as well, giving you a hard time in finishing the level.