There were things that came before this.

My dad was driving me home from somewhere, and as we pulled into my house there was a big crowd. I ran out of the car and acked what was going on. A man had escaped from a mental hopsital and was going on a rampage with a gun. He started shooting and I threw myself to the ground to avoid the bullets. I stayed like that for a while until I heard the shooting stop. I looked up and everyone had vanished, including my parents. I started to freak out, and the man appeared behind me, the gun aimed at my head. Somehow I managed to beat the crap outta him, and the paramedics came.

Later in the dream I was at this sort of party. The man who had tried to shoot me was there, except he looked like a docil, slightly chubby, teenage boy instead of the lean, balding, scary man he had been before. I was told he was harmless at that point, and we became friends.