I repeat:
What was she doing in the bedroom?
If I recall the story, she was “herded” there by 4 boys, 2 remained. Herding happens at parties all the time. It is generally just rowdy fun ending up with some smooching or other normal teen activity.
In my experience, herding is practiced when a person privately expresses some attraction and that “secret” becomes known. The conspiracy is then afoot among the friends of the two and they get noisily bustled into a room together.
What many teenaged idiot girls do, especially after drinking. Thinking they were in control and could go as far as they wanted, safely, and no further. As a Catholic high school girl, myself, I didn’t know girls like that, but I’m certainly not surprised that they were - and are - around.