Ok in the the map where it has ice and snow thats the place this is in.
Ok take your wartbog and drive it of the edge of the broken bridge stay in it till you see your guy die than look up you should see the spot you died in and that the game made you go out of the warthog it should be levitating in one little space while you fall to the ground.
Very lame brain but fun.( Note; do not I repeat do not jump out any time. ) ( Note; I only did this with a ghost but I imagine this will work with a warthog. )

If you have anything you would like to say e-mail me at drakenplazma@aol.com our send me mail on my myspace witch is plazmasam@yahoo.com.