Damn, she completely ate it on that fall. Since she's not in America I'd probably get it checked just in case. Back injuries are no joke at any age. But also, what is she? Fred (the "MY LEG" fish)? nothing about that fall shoulda hurt her foot except maybe shifting badly on the step stool.
On the bright side I learned some neat things about libraries today. I was curious on those empty cases too but never really bothered looking up why. I thought it was just to protect the book from the wooden shelf or something. Ofc Honami is in the gutter instead... I kinda forgot by now about chapter 1.
I'd be surprised if it's even in the volume release tbh. Seems like a remnant of a more exhibitionist direction the author thought about but it must have gotten into serialization talks real early with someone wanting a more SFW approach (with tiny bits of teasing)