I guess we can only hope we are cut out for it... i know that after a year application process, additional 6 months wait for placement... 10 months of training, moving state twice... i'm going to be devastated to fail at the final stage.
Although, at the same time, I wouldn't want to be passed if i really wasn't up to doing the job... i'd much rather waste a couple of years of my life than risk the lives of hundreds of people.