I had a very strange dream...?

It was a very long dream and I can only remember the end. I was in my old school. It was a large area of the school where the students could take a break. Instead of students there were these detectives but I felt that I was one of them. We were each handed a yellow index card with typed writing on it (but I couldn't read it). I turned around and saw a drinking fountain that there was a small line for. I wanted to wash my hands but by the time I reached the fountain, there was no top on it...it was basically a sink. I noticed that everyone else was soaking these yellow index cards in the water and a man noted that I wasn't. When I turned around, I saw a bigger man in a grey tracksuit talking to two guys. I could see he was angry and I dove to the ground. I was hiding behind desks before anyone else but I warned people around me to get down. He pulled out two guns and began to shoot. I thought I was in seriously bad situation so I ran and hopped over a bannister to get to an escape. I was running outside and saw a giant wave heading towards the school, and suddenly there was one inside the school...it was more of a wave. This water didn't hit me at all. As I was running down a path, suddenly there was a sand/dust storm that I got caught in. I could barely breathe. Once I reached the main road, I began to walk back towards the school. As I did, I could hear the voice of an actor over the intercom but the school was in complete silence.

Any interpretations?