In real life the daughter of a publisher and philanthropist, Patty Hearst, was kidnapped by a gang and forced to commit armed robberies. At the time of her capture, she was a criminal. In the military, recruits are forced to live a new clean and ordered life. They soon like who they have become and feel separate from, and superior to, the slackers on the outside. I have often seen this kind of force work, and the change becomes permanent.
Identification is a powerful tool.
In college, some students become elite - they will no longer go to certain kinds of churches or do certain activities, as they adopt behaviors and attitudes that are modeled for them by senior peers in their profession. Personality change happens in all professions, and sometimes in very negative ways. Law enforcement agents often have to emulate the people they are trying to capture in order to infiltrate their ranks. The danger for them is that they lose their grip on values and become the very criminals they are fighting. In one case, FBI agents barbarically tortured a man.