In the same way that he doesn't take it for granted that she can trust him with being close to her like this — holding her hand, even kissing her — the Doctor also doesn't take those moments of her being playful with him for granted. It's strange to still feel twinges of those old memories in that shared dream, the feeling of missing her so desperately and not knowing if they could ever fix it. But they're here now, they're connected to one another, and she incrementally makes him less and less afraid of it — getting close, too close, only to lose her. He saves those moments of worry for when he's alone.

"What a strange thing to carry over, though — and more that's out of our control." He's most upset with the way his memories were stolen. To have their minds played with like that —

"A bit stayed behind with me as well." This, at least, he doesn't mind; he can be stroppy about the mechanism of it while still delighting in the fact that he can do this at all, and he smiles softly when he opens the palm of his hand, revealing a few small stars and planets swirling about.