Aizawa naturally grew to care thoroughly about all of his students, after every event they’d been through, he felt more protective over the group of them. Of course, he never openly admitted this, but would display it rather in his actions.
So, he was doing his nightly dorm patrol. He’d check to make sure just before lights out that everyone was okay, and that everyone was going to sleep soon. He came up to your dorm, after visiting Mina’s and knocked a few times. Yet there was no answer.
He knocked again, nothing. He checked downstairs and you weren’t there. So he went to the next place you could be, the rooftop. There he found you, sat on the rooftop ledge. “Kid, what are you doing up here?” He asked worriedly, walking over and crouching down.