As was stated, you can weave in and out. Help out your healers by mitigating damage by keeping Stoneskin on yourself whenever you can, using Second Wind whenever it's ready, and using Bloodbath with your heavy damage WS's. Hell if anything, you can just Invigorate then stand out of Sear range in passive to get some HP back while your TP ticks up, too, or save Invigorate for whenever he jumps.

I've had many Lancers that would AA from within Sear range and fights still turned out OK, and PGL's Second Wind is much better so you shouldn't be as much of a burden as you would expect when your group gets enough experience with the fight. MP for your healers really shouldn't be an issue unless Ifrit decides to constantly spam Eruptions on them or they haven't had much experience with the fight.