Not going for the Iguions?
I think I could do it if I blew a camp before Iguions themselves. 2x casters with 2 shots of Quake each (which also makes the trash manageable lol).
First turn: Mental Breakdown on one, Power Break on the other, Boost on Cloud, Cloud retaliates, healer casts Kirin
Second/third turns:, spam 4x Quake, Cloud uses Bladeblitz, others finish off the low HP one (which got hit by Bladeblitz, 4x Quake and Mental Breakdown, should have ~15k HP left).
If that works and no one dies or gets stoned in the process, it's probably a home stretch to kill off the other since it already has Power Break on it.
Just a little scary to blow a Mythril to camp since that kinda sets a precedent going down a very slippery slope, since Mythril is such a finite resource. I mean, yeah, if you clear/mastery it you get 1 or 2 4* Summon Orbs, but it's still a huge risk.