you were walking through the hallway.. looking for your victims.. they were hiding around the school.. you locked the whole school.. and hid the key.. the whole school was dark, you had to get rid of your rivals.. permanently.. you were really powerful, so this was easy, all you had to do.. was listen and find.. most were dead..

(It's like a game.. if Deku dies the world resets back to a safe spot that Deku was in, he's the only one that remembers it.. his objective.. is to escape..)