[As far as Dazai is concerned, there is nowhere under Echo and Aurora's auspices that's truly private; he suspects they are watched at every moment. And without the benefit of context for where in the timeline Chuuya was relative to himself, it's better to get things squared away on neutral ground. Besides that, from what he can tell, others here are hesitant to offer Tatianna any information to begin with, and whatever they have to discuss will make little sense to anyone unfamiliar with their world. He's already determined they're the only three here.

He doesn't bother to clarify immediately that the spiel, as it were, leaves some important details out; that can wait. This is now the second time new information has thrown him for a loop. So there were vampires involved in Dostoevsky's plan, but what did they have to do with framing the Agency? Where did they fit in with what Fukuzawa told him about Fukuchi?

And Dostoevsky's ability ... well. Alright, that's valuable information to have if Echo ever decides to include that demon in their "tests" of sorts. If there's any chance he returns to his own time and remembers this conversation, it also means he can take care of Dostoevsky before he has the opportunity to frame the Agency for whatever crime it was, as well.

He takes a breath.]

So Dostoevsky's a vampire now? And I'm literally the only person in the world who can kill him, then.

[He looks ... so cranky. This sucks. Can he go back to antagonizing Chuuya yet.]

You know, I'm getting rather tired of this kind of responsibility. I can't even go drown myself in the river anymore! It's really unfair!