"I live here, though... Hang a sock on the knob if you don't want me to come in."

Living almost your entire life with roommates, you learn the tricks. Of course, his old roommates would still be alerted to his entrance by the sound of the door opening...

The question makes him pause, though. He hadn't considered that yet.

"Throw something at me." There's only one way to find out, after all.