It's not hard to read between the lines with her. She's a creature of habit, and this case, it means she was thinking about work and got half way to the lab before remembering herself or the time.

He makes his way back to the kitchen, leaning his back against one of the counters.

The part that makes him happiest - beyond the fact that he knows her well enough to tell - is that she knows him well enough to call and ask for company. That she'd want it in the first place.

"Chinese? Can you ask them to double mine?"

Steve still feels sheepish asking, even if his physical requirements make it a reasonable request.