incarcerator - how this is possible?

For info lv65 Kole usually does arround 3.5 to 4.5k dmg (I think its 100% physical but I may he wrong and there could be added fired mixed in [in HC I may advise you to kill the caster first cause his exploding body could cause you such frustrating death ] ♥]
Incinerator does arround 3.5 to 8k dmg and I think its the same for Carnage.

I usually am always full time "granited" with granite of reflex and never face tank him, running in circle and offering some target to play with. And for a measure of security I use charges from my life flask assuming a hit.
For such bosses I like to granite + jade and some steadiness mods.
If a hit culd bring you to half HP you7 better have some Unwavering item or passive or a lot of stun recovery