When (if ever) does it fail? Edit
Does this ability work for all attacks, or are there exceptions? I'm thinking, for example, of Aran's Arcane Explosion, but I'm sure there are plenty of other examples which would be of interest.... 100% cheat death combined with well timed Cloak of Shadows could allow a suitably specced rogue to keep up DPS on Aran during several AEs (first Cloak of shadows, second cheat death, and discretionary for the 3rd, etc..) , and be able to interrupt while the rest of raid gets back into position.
 depending on how AE-happy Aran is, cloak of shadows should be back up for the 3rd, Cheat death might not be (one minute cooldown); then it's a question of whether you want to risk it with only CoS (still a 10% chance of going splat...)
... actually that brings up some other ideas... there are various attacks with known, fixed amounts of damage output (in Aran's case the pyroblast... but again, other examples surely abound)... if this ability completely negates the attack that would otherwise have been fatal, then it would be interesting to try to arrange it so that such attacks *would* kill you, and thus avoid them entirely through this ability (IE arrange to have less than 7500 health for said pyroblast). Of course it's not entirely clear to me how to arrange for such a reduced health level without coming into risk from other nastiness, or giving your healers a heart attack... but maybe someone has some clever ideas there..
--Sallick 18:17, 23 March 2008 (UTC) (sorry, forgot to sign the first time)