You and Kirishima got in a big fight while Bakugo was out buying stuff. Bakugo comes back and sees you two fighting. Bakugo breaks up the fight. You walk into your room. Bakugo goes to comfort you. Kirishima comes in a little later

Kirishima: in a sad and guilty tone I'm sorry...

Bakugo: in an annoyed and cold tone You should be.