It's easy. I've done it every time I fail the save.
Either 1) Get a good fortitude save..
Or 2) Lots of HP, Firestorm Greaves + Tier 3 Fire Absorption GS item. (78% absorption)
So if you have over 440 HP you live.
Arcanes can throw Fire Shield (Cold) to make the damage 1000, then the 78% absorption can kick in.
Quit whining, it's just Turbine's way of making Slayer Arrows + Ioun Stones something easier to handle.