Her behavior at the beginning...

It was very hard to believe that any woman in that situation would lack such awareness and behave that way before two strangers and her boyfriend. Alone in some strange house and she's walking around like a brainless slut in skimpy outfits and making a spectacle of herself in front of three men who are practically salivating over her. I felt like they went way overboard with that.

I'm not implying at all she deserved what happened, I'm saying I don't believe any woman, much less one with the traits we see later and who almost certainly had attracted unwanted sexual attention before would behave like that.