Going back to a hotel with someone is not consent to sex. And if she was drunk enough to be incapable of consenting to sex with CE (regardless of him acquiring a key and letting himself into the room which IMO is irrelevant...she could still technically have consented or not consented when he was in there) then she was also incapable of consenting to sex with the first one.
There is a legal defence in that if he had 'reasonable belief' that she consented he has to be found not guilty. It doesn't mean he didn't rape her, it means he believed it wasn't rape.
I know that might sound difficult but try this. A man who sleep walks gets up in the night, still asleep, drove his car to his in laws' house and kills his MIL.
This actually happened in Canada in the 1980s, the killer was acquitted of murder because he was asleep. That doesn't mean the killing didn't take place, it means he had a legal defence.
Another thought, you are semi conscious, naked, a teenager and you find yourself in a hotel room with one man. Another man comes in, both are fit healthy men considerably bigger than you. You realise there are two more men outside the room shouting through the window. You hear the men discuss 'having a go'. How much choice do you really have? What are they going to do if you say 'no'?