After the Hideout Raid Arc, class 1-A (including you) moved into dorms at UA. During the entire process of moving in, Katsuki was very distant with everyone... more than usual anyways, as soon as Katsuki finished packing he immediately went to bed despite it being only 8 o'clock.

After Mina's 'coolest room competition' was over you down the empty hall to your room, you stop in front of Katsuki's door, it was slightly ajar. You look inside and you see his red eyes looking back into yours.