Steve doesn't back down but he doesn't get any closer, either. He keeps an eye on Sam, tries to sort out a response to that that won't make Sam cut, run, or feel ... what? obligated? Put on?

In the end, he just doesn't know, but wolf-nature and Steve nature combine to have him finally leaning lightly against him. "You need to spend less of your time worrying about me." Not that he's not grateful; he is. He just worries bout Sam back and doesn't want to be Sam's problem.

Kind of the opposite of what he wants, actually.