@pizzalover96,
You did a smart thing getting out of there fast.
The best sexual assaults (there's a contradiction in terms) are the ones that never happen. You may or may not have prevented one, but the outcome was the same - you were unaffected.
To add, your friend sounds clueless. She is presumably a big girl and perhaps the thing to do is to tell her you are no longer going to save her from herself. Then maybe hang out with other people. Your personal safety has got to come first, and if she is too stupid to figure out that her own personal safety matters, well, you are not responsible for her.