Rolling Stone (yes, THAT Rolling Stone) had an excellent article on Scientology in their last issue. By the time you make it to the level where they tell you about Xenu and the volcanos, the amout of time and money one has spent must add up to one hell of a case of cognitive dissonance. I'll bet that's what happened to Cruise.
http://www.rollingstone.com/news/story/9363363/inside_scientology?rnd=1142611560953&has-player=false