This is the hardest encounter so far, we did it with a paladin and holy priest with gheal spec going inside. It is ok if the priest let his stack fall but if the paladin let his fall we would not even try and would just wipe it instantly. We were at about 80% when we hit lust, with a 30 stack that 80% did not even last the full 45 seconds of it.
We also had a tricks and a misdirect so I solo tanked it for some extra dps. Worked rather well for us. We had an aff lock and spriest dotting suppressors and then getting back on adds. Used a frost trap under every single abom corpse, hit swipe once when they were all up and then started kiting with a tricks fan so they almost never hit me unless I was slowed. Landing a bash on the casters they were dead from full health before the stun ended. Let the blisterings be kited, we had a hunter and a DK and by the time they even reached me they were almost dead and I was just taunting it away from blowing up on the casters.
She needs to be healed before the 7th portal or just as it is spawning because that is when you just get completely overwhelmed by adds