head-biting-scene. when does it happen?

okay, so i've been wanting to rewatch the scene where the t-rex bites of that dude's head for 10 YEARS NOW, and i JUST found out that it was this movie (i never knew the name of it. i started to believe i had just dreamed it up) and i just fast-forwarded through the film so i could watch JUST this scene, but i didn't find it. this is what i remember of it:

a man is standing in a warehouse and a t-rex shows up and stand over him. the man is like :O and then the t-rex bites his head off and slowly rips it off his body. the man's body remains standing and his entrails are all stringy, like when you bite into a hot pocket.

when does this scene happen? beginning, middle, end?