There has been some kind of apocalypse and I am in a multi storey building with a bunch of people. There are people outside the building trying to get in with us or get to us. First we are on the roof and we have put a rope across one side with blankets or something hanging off it to kind of block off that side view. Next thing I remember is that there are a heap of people coming up a staircase into our building, we don't really know what to do. Eventually we sort ourselves out and stop them from coming in but some got in. I think we started shooting people who were coming up the stairs. Can't really remember much after that.