Posted: 28/02/2015 at 11:59
Maybe he went over there because he was brain washed into thinking he could do some good. Then once they physically got their claws into him they may have forced him to carry out these actions through conditioning and blackmail. We don't know what pressures are put on individuals inside the organisation.
Personally I have no idea what happened to change him from an average person into the monster he appears to have become, but I just wanted to throw another idea into the mix