He was wrong, of course. Watson could have left her, but he didn't. It wouldn't have felt right. "I'd like to get you some water, but I don't know if it's safe to go out. Can you make it a few more minutes? I don't want to go into the hall until you're ready to run."
To, ah. Someplace. He'd been out into the courtyard, but there were clearly walls and he wasn't sure he could get her over them. Hmm.
"...I could always cause a distraction. If you'd be fine on your own, I could buy you some time."
But then he wouldn't have the opportunity to ask her questions. Also, he was worried - even if Buffy were mobile, she couldn't be feeling well. It was all for naught if she got recaptured.