>Several days after falling in this hell
I don't know if it's a mangaka's mistake, or a translation one, but, at least according to original WN/LN, it's been, what, about a month since he's fallen? He's actually been lying after loosing his arm for two weeks and he descended some fifty or even hundred floors after that before reaching the prison floor, iirc.
It irked me when I read it the first time (before reading LN), so just a heads up.