Dropped off an initiate inside the Nautilus room. Level 70 Cleric, pulled waves of 5-6 of them and ae'd - ds potion, clarity potion, and steadfast servant for free heals and haste.
Got the vial after about 2 pulls (roughly 10 mobs).
Their tendancy to gate isn't exaggerated... had a couple at the end who gated at least 3 times each. Get them to around 16% and throw a nuke, they'll try to gate as early as 15%.