Steve is perfectly aware he is being stared at suspiciously. He is also perfectly aware that there is no ulterior motive beyond... yeah, trying to take care of Clint, he guesses. Not a lot of benefit in leaving Clint alone later, when later he's going to be at least banged up. Definitely no benefit in adding any additional trips in and out.

Which is to say, Clint stares at him and Steve looks back and looks bewildered while he does it. He does not have a poker face. He's not saying anything, which makes it easy to ignore, but his expression's pretty clearly asking what the fuck.

"... All right, then." Then fills the mugs and hands one over to Clint, and leans back against a counter so he can drink his own, around getting his own protein bar down. It'll take him maybe three minutes and he'll grab his hat and sunglasses and go.