Dream About Train Assassin

I had a dream the train I was on to college began to fall apart because an assassin tried targeting someone on my train. The bottom part of the train fell apart and people started flying out. I ran to another carriage and sat in there holding onto the safer side of the train. It came crashing into the stop before college and I ran out as the journey was cancelled. Everyone off the train kept saying they could see the assassin but all I saw was a moving shadow on the buildings above.