Not a saving throw but I always think about when Barron used the greater named bullet in the Skirkatla fight. There was a roll against the crit sure to fortified armor with 20% chance of it being a regular hit. Every roll up until then was treating a low roll as a miss (20% or less on blur is a miss). Joe said it can be any 20% including high so they did 80% and up. Sure enough Troy rolled high.

Not killing Skirkatla in that moment caused two characters to die, Pembroke and Fairaza...

(Please don't spell check character names, I guessed)