Need help remembering a movie I saw as a kid in the mid 2000's. It was either from the 2000's or 90's I would guess. It features a girl getting date raped by same kind of frat. It's at night and there's some kind of "dark world" thing going on. In a later scene, an elevator has someone's corpse on the top of it and it appears in the open elevator shaft.

>pic unrelated