Given what's been pulled out recently, my last post was clearly very way off mark - looks like there's room for quite a bit more material.
And while on that subject, dammit, this week's issue did it again. Yūsei Matsui is just brilliant about pulling setting up things subtly so they're not asspulls but at the same time, until the reveal no one notices. Which for a manga about assassination is highly appropriate.
I don't want to spoil it, but when there's the 'map' of the area the class are fighting in, one marker doesn't seem necessary until the last couple of pages.
(And damn, the girls are kickass in this arc. Kanzaki, Hara, Hayami, Nakamura...)