Jerky nod.

"Yeah. Definitely." Because now he was going to to show up at the door of the lab to make good on that if he had to. "So, uh--" as he realized that he'd still been holding that stupid shirt all this time, knuckles of his left hand nearly white from his grip, "--here."

He was going to replay the moment of letting it go and tossing it to Tony over again in his head a million times, thanks.