Billy had been unpacking his books and getting his bag sorted for classes when he heard the knock. He wasn't expecting anyone. Teddy would have just used his key and most of the other Titan's would have just called.
So he was a tiny bit surprised to see Mia on the other side. He pulled the door open to let her in, rolling his eyes at her comment. It wasn't like anyone at the school was going to be bothered by the geeky kid with his Doctor Who obsession.
"Teddy's not here," he offered as he went to the mini fridge and got them both a bottle of water. Mia and Teddy were close to each other. Billy and Mia, at this point, were teammates. He had to assume that she was here for his boyfriend, which was fine. He walked back and offered Mia one of the bottles as he gestured to the couch.
"You're welcome to a seat if you want. Is something up?"