Ok, that puts my mind significantly at ease. It looks like you were rocking a sustained 2k HPS during the soft enrage, which is a number I can actually reach (I sustained 1970 HPS for over 4 minutes solo healing the second phase of Operator IX, and I didn't use my ammo management CDs).
Not to downplay your achievement at all! That's still an *insane* amount of healing, and you deserve mad props for pulling it off. I'm just glad I won't need to reroll scoundrel to attempt to replicate it. :-) My main concern at this point is I have no damage abilities that I can pre-cast like you can with XS, so the hard enrage may be a serious problem.
I was talking to our sentinel last night, and we're curious: is there a reason you didn't just leave Stormcaller at 10% and nuke Firebrand? That way, you'd only need to heal through a soft enrage for a few seconds.
We did try leaving stormcaller at 10%, but after that no matter how many times i used my threat drop ability, they couldn't take the agro from me and after a few seconds i was tanking both tanks. Everyone was taking damage from both cleaves, making it impossible to heal. We probably could have done it that way if i stealthed and positioned myself better, but we changed the tactic before trying it.