A small group of people get trapped in a diner by ravenous flesh-eating rape-beasts of undisclosed origin.
During the course of the siege, one of the women gets a leg chopped off and apparently dies from blood loss. Some of the remaining survivors decide to use her corpse as bait to lure some of the monsters to their death. They strap explosives to her body with duct tape and plan to lower her body out of a second-story window.
Unfortunately, she wasn't dead, just unconscious. They were just lowering her when she woke up. That's pretty much where this clip starts.
This is an incredibly fun and squicky movie. It's cartoonish over-the-top gore and craziness.
At first I wondered what the hell was happening because it looked to me like she was getting face fucked by a monster, then, when it turned out she was, I felt better about myself and my perceptions.