Umm...what happened?

I was trying to get to sleep last night, and I was quite tired. I distinctly remember then seeing a man walking into a train station, then a BANG, and I jolted awake. I was feeling very tingly after that, and was wondering what happened. Did I pass out, have an extremely short dream, or hallucinate...? :?

That's something called exploding head syndrome. It is when you are peacefully sleeping and then all of a sudden you hear a loud noise. Nobody knows how it happens, but one theory is that it is a seizure in an area near the area that perceives sound. Don't worry, though, it is harmless.