MAC gun glitch

On the Return to Sender part of the Cairo Station in Halo 2 campaign, there is a metal object moving back and forth, which is the loading arm of the MAC gun. When it moves back, a MAC shell is loaded into it, and when it moves forward it loads the shell into the MAC gun. If you get in the way of the loading arm when it comes forward, you will be killed, but you will drop through a hole and see the hangar in the "Return to Sender" cutscene.

Also, you can get stuck in the MAC gun barrel and get shot out into space. Just stand in front of the reloading "metal object" and wait for it to push you into the barrel. You will die and get shot out into space, just like a MAC round. Elites can also get stuck in it, which makes it difficult, if not impossible, to finish the level. Standing on the opposite side of the room, where the loading arm receives the MAC shells, will have a similar effect; that is, if you stand directly behind the loading arm when it pulls back, you will be crushed by an invisible barrier and sent flying. Sometimes you will be thrown out of the level and killed.