If he gets even angrier, you have a decision to make -- one that ends with your friendship, or with the possibility of this woman. Are you prepared to do that? Think long and hard about that before you move forward. Please keep in mind that I don't think this girl actually wants to date you. If she did, she wouldn't dip in at 2am. And she would have been all over you when you tried to hook up with her instead of acting like she was doing something wrong.
After you talk to your friend (AFTER!), contact her and say you'd like to talk.
If she agrees to do that (sober, and preferably by the light of day), be very direct with her. Ask point-blank if she's interested in you. If she can't say with certainty that she is, she isn't. If she acts cagey and is all, "Oh, I don't know, it's all so confusing” or "I'm just really messed up right now and need time to figure things out," she isn't. If she turns things around on you, she isn't.