Anxious about Neighbor

I also posted about this on another thread.

My neighbor last night had someone over pounding on her door and yelling her name. Then a few hours later she or the visitor was moaning screaming and sobbing all night.

I asked her about it this morning especially since her lights where left on and her door unlocked and open. She said she had no idea what had happened, she went to a bar and sorry about the late night, that her friend took an hour's cab ride home, and that she herself woke up with no pants on. She apologized for any noise or commotion made.

I'm nervous if it happens again and also what the heck happened?!