How can one fail the crucible? You mean backing out from fear of being killed and taking Apocalypse's mercy? That is interesting but I think that can be easily misconstrued by audience as cowardice,but remember depowered is not dead.Some former mutants could doubt if the resurrection protocols are what they are.So anyone refusing to die because of not only fear but doubt.Say for example a devout religious mutant not too different from Nightcrawler can't be ridiculed for worrying about all the questions Nightcrawler posed in the story