It's definitely a familiar tone, one which wouldn't really work anymore. Not that it ever really worked, not on Adachi's true nature, but as the idiotic partner person it was super effective.

It shouldn't have effect on him now, especially. Not after everything. He should be able to lie to Dojima's face, just like usual (even if Rise would likely mess that up). Yet something was compelling him to tell the truth.

Adachi does try to fight it. But it's just too strong for him to resist.

"... March 20th, 2012", he finally says, his expression dark. The date is significant, no matter what timeline Dojima comes from, so he doesn't bother hiding behind the fool's facade anymore.