There's always a defining moment of each volume where the girls just show they have no morals and do something you wouldn't expect, something insane like rob a bank or beat up and rob the homeless.

Part of what makes volume 5 feel strange is it lacks anything like that, it lacks a moment that really screams blue Archive. its too straight forward and the melodrama is too normal, any other chapter would shit all over the melodrama by having the characters do the dumbest thing possible to solve it.