Dream About Train Accident

This dream was about

I dreamt about me and my schoolmates were in a subway station waiting for a train and one of them was on the rails for some reason. And i told her get up there was a train coming she just didn't reply and stood there andthen got hot by the train and when we all saw her dead body we were sad and i was like : oh my god.. WHY??! i dont know maybe i had ptsd after that in the dream or something, also when she got hit by the train and then i said omg while being scared i woke up instantly.