[Akechi may be the only one sad that he can't return to New Beijing. While he knows the lower levels are left to rot, he rather enjoys the surface ones in a very selfish and shallow way. And now he can't.]

They're making a move but they waited for the opportunity. It means that they were hoping that someone would slip up, leaving a door cracked open. I doubt that this is only about her vendetta. That still seems like a grab for sympathy, what with all the people who died.

[No, Akechi doesn't seem to think ... it's sad ... that those people died.

Whoops.]