Prompt -- you are laying in bed in the dark and you glance over and see an odd shadow in the corner of your room. you're about to turn on a light to see what it is when you hear a voice in your head that says, "don't move. they're watching you"
You finally realize that everyone on the train is completely still, some seem to have stopped mid stride walking down the aisle. You receive a text"You will become one of them if you don't get off this train within 5 minutes.