It would be pointless to tamper with her memory, only to speak freely about it now.
[He is concerned, now. The situation had been easier before, when he thought she simply wanted to forgive him, to return to the past and hope to stop him and Yuuki has always been very good at making him hesitate.
He didn't consider she might not remember.]
You don't remember, Yuuki?
[A piece of him is disappointed, because he does want to be with her, to hold her, even though he knows what is best is for her to leave him. Now, though, it raises more questions. To be able to hold two Purebloods in this place is no easy feat, but to manipulate one's memory...]
We discussed this once before.
[And if Yuuki's memory is tampered with, what is to say of his, or Kiryuu's?]