The more this manga advances, the more it's story… irks me? Confuses me? I'm not sure if those are the right words to describe it, but I think they are the closest ones to my opinion. I was looking away from its conveniences and the protagonist's plot armor so far, that's not what I came for after all, but it's getting a bit tricky to ignore it at this point.
I assume that the hag placed those zombies in that room… but how? Was she, and the people loyal to her, able to capture that many zombies? Was a group of men already in the reformatory, and transformed there? Why haven't they escape of that room? Or, how did they manage to keep the zombies inside? Given how they are using the zombies, they look quite sure that none of them is going to escape (let's see how that goes in the future). Either that, or she can control the zombies to a certain degree, but that also seems a bit weird yet possible right now. This definitely needs more context.
Anyway, now that this “punishment room” has appeared, I'm waiting to see the main cast getting into the reformatory. I assume that someone will be captured at some point, and the rest of the cast is going to do a rescue operation. If that happens, I hope that they have to get in the “punishment room”, even if it goes just like with Saya and the giant zombie in chapter 5, which is how it will probably play out.
Also, Rin and Ren remind me of Chisato and Takina, mostly on design.
To anyone who reads this, sorry for the rant xD