"Don't you dare be," because what if he had said it? What if he hadn't assumed she knew? Where would they be then? What would they be doing? Would they have even wound up back on earth again? There were so many questions, so many points in time that fluxed with the thought. Oh, if he were an unscrupulous Time Lord...
She said there, giggling a little and looking like she'd been caught with her hand in the cookie jar. The Doctor looked much the same way - but his hearts were singing! He might not ever be able to say those words to her; but, he'd managed his kiss. He'd managed to keep his head level and hadn't said anything particularly stupid. And he knew in the end she'd still be so furious; but, he had this moment.
"Never," he shook his head. "Well.. once, but it was complicated. Extenuating circumstances..." His pose was mirroring her own as their stance turned very near to an embrace, with his hand trailing up and down from shoulder to elbow.
"I really ought to go... this is dangerous stuff," yet, he wasn't moving. Oops.