Cas had been in the bathroom since he arrived, he had been hiding from the football team. He had said something wrong, and pissed them off, so when he heard the door open he pulled his feet up and remained quiet. He listened as the footsteps went into the stall next to him. Its was quiet until he heard the first sob, not a jock, but who? He used his phone's camera to peak into the stall and he seen non other than the loner, Dean Winchester.
He kept watching as Dean pulled something shiny from his boot. Was that? A blade?! He got a little worried not sure if he should move until he saw Dean take it across his arm, making 3 deep cuts. Dean didn't move for a while until the blood started to run down his arm and drip to the floor. He grabbed some towels pressing them to his arm.
Cas had seen enough, he stood and opened his door and quickly opened Dean's, seeing his scared and surprised look.