While we had an idea that Bell would survive (thanks to the various hints as well as how she was captured and preserved), it's still nice to hear how it would work. Not to mention, it would explain why the head chief primarily uses her as a punching bag and/or toy whenever she's in a mood as Bell would be able to recover from nearly any effect that the head Chief does to her (save for having her ability canceled).
That said, I'm not surprise Yuuki and his group are struggling against Rairen, as most of their groups abilities and attacks are physical based and Rairen boasts incredibly high physical defense. Tenko defeated Rairen easily mostly because her spacial attacks bypassed almost any physical defense, and for the most part that's not something Kyouka and Yuuki can replicate, at least not by slugging it out.
It'll be interesting to see how they go against this.
I'm calling it now, Rairen is gonna join the harem
I'll laugh if Rairen was actually female this entire time and/or has a female form.