I never saw any statement from the people involved as to why she left with him.Just as I never saw anything that the roommate even knew about the altercation that night.I am still trying to figure out why she brought him back to her apt.I know what people are going to say but according to HT her boyfriend practically lived their so it is pretty likely he would have found out.If that was the plan I would think they would have went strait back to CR apt.
The only thing I can think of is that she wanted shoes. It seems like she could have just gone back to Kilroy's but maybe she really had been kicked out?