Go rune and laugh in the face of death.
Yeah, but no.
Even at -80%PDT sike flail gonna deal like 2k on RUN, which is managebale, but totally destroying backline jobs and obviously trusts.
Normaly beating Mireu involves multiple sethleus spamming rejuvenation for recover and tp, while the crowd of people makes somehow safe for people to take dmg (idk, maybe is the AoE target limitation?).
So, once you wipe, its quite hard to recover because everyone gonna engage again, then first flail or that move that strip trusts gonna expose all the players.
If you actually want to survive with real suport, you gonna need to resort ether to shadows what i dont trust much because he flails too often, or having some of scherzo + Earthen Armor.