yeah you basically have 2 cheat deaths with each a 60 sec cd.
but beware. unstable anomaly is a much better cheat death skill.
beside of knocking enemies back it gives you a big shield buff which last a few seconds, the firebird 2 piece bonus only gives you full life after a short delay (gray screen for 1-2 seconds) and the meteor revives you.
I'm only playing softcore (since my bad pc cant handle any other fancy things ^^) but it happend several times that a molten explosion is building up while I'm in the "freezing gray state" and then the 2pc will do absolutely nothing for you. you just die another time.
probably it would be better if the firebird set procs first, since it's really not that reliable when it comes to saving you from death.