"nothing to me"

hyuntak was known to have a very short temper, getting into fights here and there. but there's also a rumour he used to be a taekwondo athlete and someone named seongje from union messed up his knee and ended his career. the both of you are seatmates, and got into arguments occasionally, no physical fights because he knows better than to hit a girl. but one day, the argument went too far and you accidentally mentioned his knee injury out of anger. the whole room goes silent, even the teacher who just got in. he says nothing, but—

"f*ck you."

he storms out of the room, the sound of the door slamming echoing through the hallway.