Hydra & Triumvirate

I'm on the part where I have to kill the hydra, but my previous experience with it is that the tank we had, 5k HP, took a hit with full HP from Triumvirate which left him with less than 900, what follows after 3-4 seconds is another Triumvirate which we could not top him off quick enough. Triumvirate itself seems like a 0.25sec cast time, it's impossible to interrupt, so how do you avoid this attack? I hear you can run circle around the boss but once the cast bar is finished (which happens quite rapidly), is it still avoidable?

Thanks.

Triumvirate is an ability that can be split between any amount of people in front of Hydra. So, if you use two tanks, make sure you they're both in front of Hydra to split the damage of his Triumvirate ability.

Also, as a white mage, one protip is to use stoneshield more than you use cure. Helps absorb most of the damage if you're planning to one-tank hydra.

Having a Scholar around allows for more to cushion the blow a bit.