Shimamura is likely some kind of genius who's bored by regular classes.
In a logical realistic way or reasoning, what the hell could Adachi ever be tired by in this situation? I guess the mangaka wanted another chance to make his dark-haired heroine look weak.
I would make a bundle if I bet against all of you every time the question came up: "Is the mangaka going to portray the dark-haired girl or the blonde girl as being frightened of bugs and/or haunted mansions?"
I'd love to play that game sometimes.
So... The mangaka was able to make his dark-haired heroine look weaker than his blonde heroine again, but we still don't have any progress.
Maybe next chapter he'll put more effort into the story and less into his weird hair-politics obsession.
Just push your girl down and go dirty on her, Adachi. You know you want to.