That involves acknowledging that he was the one who made the mistakes. And it's awfully hard to, when the closest thing he made to one is right before him, very much alive and well. Perhaps he shouldn't question it, either.

Or why Tadashi hasn't yet walked away.

Nonetheless, he doesn't, either, allowing this surreal sort of conversation continue. There's still a normalcy to it, one he's lacked as of late, and has, perhaps...missed.

"Still? I'd have expected you to hit the ground running." There's a jest he could make there, something about Tadashi slacking off, but even with the reach for something of the past he still falls short of the goal. No amount of pretending or ignoring will change the fact that things aren't the way they were before, and likely will never be.