It could have happened while she was asleep, then she woke up and figured out what happened. Or since they were at a party alcohol may have been involved.
I never buy that as an excuse. If you choose to drink then you need to understand that the things you do while under the influence may or may not be agreeable to you when you sober up, but it was YOUR decision to drink so you get to live with the consequences of your actions. (When I use the word you in this post, I don't necessarily mean you Moiraine.)
An excuse for what? Seeing as I was replying about how the alleged victim gave a range of 2:30-7 or whatever, and her not knowing what time it was may have been because she'd been drinking, it seems as though you're implying the excuse is for the rape. Getting raped is the consequence of the rapist's actions. Not the person who got drunk. People shouldn't have to stay sober just out of fear of getting raped.
If that's not what you meant then I'm not sure what you're talking about.