Well. It's not every day (which is to say, not at all) to see Asuka knocking at his door. Shinji didn't think she'd want to come see how he was doing, anyway. He never did the same for her.

Nonetheless, he steps back to give her room to enter. His roommates aren't around, which is probably for the best considering their sharp tongues...

"Oh, right. Sorry. I wasn't expecting you, so..."