Buffy. He hadn't expected that person to be her, but perhaps he should've associated the sounds of working out with her. Kirk had been going out of his way to avoid her; there was too much of a muddled mess in his head to know what to say, hence his loss for words at this moment. He doesn't know how to respond, how he even feels. (To be honest, he's avoided thinking about it, too, thus preventing himself from really sorting out his stance. Avoid, avoid, avoid! That's Jim Kirk for you when things get intense outside of his comfort zone.) He hasn't spoken to her since he told her to leave the ship after learning that Spike had kissed her.

He puts one of his diplomatic faces on out of a lack of knowing how to present himself in a situation he doesn't have his footing in yet. "Yeah. No problem. They seem to have a mind of their own, sometimes."

Not helpful, Jim. She knows this, already. At least he found something to say instead of remaining silent.