There are many ways this could go wrong morally or legally. Without being there, no one can know. (Which makes it dangerous legally).

Just because she vomited doesn't mean much. Especially, since they were "pre gaming". Idiots in college would often slam shots or beers in drinking games, throwing up before they had a chance to really absorb much alcohol.

Morally, it depends on the power dynamic. How drunk was he compared to her? In this case, it sounds like the OP wasn't drunk and made the safe decision. Even if he would be morally/legally right, the situation with the bf would probably involve a ton of unneeded drama.