And just as easily as it went up, Akira' s mask falls again. He stares at Akechi with a dagger's sharpness, eyes flitting back and forth over his face, looking for a lie he's not finding.

"That's because last I checked we hadn't beaten Maruki."

He had been already forming theories on why Akechi was back to his old self but not trying to kill him. Maybe being dragged here had severed their connection to Maruki's reality and he had defaulted to an earlier "state"?

Though if he was honest, even in that reality a part of him doubted. When the insomnia was at its worst and he was nothing but paranoia and guilt he often convinced himself that Akechi WAS aware. That he was playing along with the new reality just to torment him. His own personal Mephistopheles in this Faustian hell Maruki had gifted them.

But what Akechi's words are implying is something completely different and infinitely more terrifying.