I'm a Black Mage. I usually pop up my Manawall at the start of the combat, cast Eye for an Eye on pulling tank and start fighting at the other side of the room, away from everybody, main reason being I avoid everyone's Weight of the Land and I don't risk the others with my own plume (there's enough room in case anyone want to run backwards and not to the sides). Obviously, I still evade my Weight of the Land, so I don't take any damage at all.
Note I do this just on the first two plumes, gathering back with the group for stomps. I even use Manaward for them so I can mitigate most of the incoming damage.

So today I've found this White Mage saying s/he needs waymarks for running south in case s/he gets caught in gaol (really!?). I said waymarks are very distracting when running The Navel, and I got this:

(White Mage): Shut up, Umo. You stand behind like idiot. Gather together with us or no heal.

I was literally shocked. Not because of the insult, I don't give a damn about that. I don't understand why this healer got mad that way. I mean, I'm not taking any damage and I'm taking a plume away from the rest of the party (once more, just first 2 plumes). What's wrong? Why this healer panics when a character is away from him/her and NOT TAKING DAMAGE?
I haven't found a single healer going mad because of this before, so am I missing something? I'd appreciate any insight from a healer point of view.

PS. Yes, the healer died. Several times. On the other hand, I didn't.