[ He just gives A Nod at the first part.. he knows most of the others are ahead of him. He knows the next battle is Toba-Fushimi, and all he knows from what Sano did say is that it's going to be a mess.. and judging by the end result of the war that he knows, none of it is going to be pretty after that.

Details would only make it more deepressing, so he doesn't press for more. It's better to make sure Saitou is well-informed, because if there's ever a level-headed person in the Shinsengumi, it's him. They can use that. ]

Sano and Heisuke also remember being in that place. Souji remembers being in another place called Haven-- apparently there's just a lot of these places around that kidnap people. [ He sounds a little grumpy about that, since if anything goes against Shinpachi's ideals, it's these shitty places.. but he already shut down one, okay, clearly this is just the next one. ]

You and Souji were both with us in Zelien too, but neither of you remembers it. So don't sweat it too much that you don't have any memory of it, as far as I'm concerned, you're you no matter what. [ He treated Souji the same way too, after all, regardless of what he did or didn't remember. ] It just means we have a little more experience with these kinda situations.