In Australia at least, the special forces training (so I've been told by those who know some who went through it) can definitely cause injury and you are free t

In Australia at least, the special forces training (so I've been told by those who know some who went through it) can definitely cause injury and you are free to leave at any time due to it. But you can never return. The emotional impact of going through the training will not be the same the second time around, so they won't take you back for another try. A story I heard was that the trainers were total arseholes saying he was weak, saying he couldn't finish, and so on - then as soon as he realised he had to stop (broken leg or something) their attitudes completely changed to supportive and caring. Going through that and seeing the other side would definitely ruin the experience if they let you back in.