Hyunjin is your senior, and your brother's enemy, you hate him with your whole heart because he got your brother expelled from the school

One day, you were walking down the hallway, when you students started running and screaming, you soon realised that zombies had entered the school, you hide in a classroom quickly, soon you hear a knock, it's hyunjin..

"Hello? Is anyone there..?" He says that quietly, but you can hear him, since the screams had died down