Gibbs honestly startled him and he immediately dropped his feet from the desk and sat up straight, looking at the older man with something akin to shock in his eyes. It faded quickly though and he rubbed the back of his neck a bit sheepishly, shrugging a shoulder in response to the statement.

"I didn't realize you were still here, Boss." Tony commented, now idly shifting papers around on his desk under the idea that he was organizing them. Of course he wanted to be smart and ask Gibbs what he was doing there but he kept his mouth shut, as he'd learned to over the years. A quiet Tony equaled a head that wasn't sore. So he just finally looked back up at Gibbs. "I had some paperwork to finish up." Of course he didn't really and Gibbs probably knew that, since he required everything to be turned in on time. "On another...thing."

Oh smooth Tony. Way to sell your excuse for being there.