I think you're right that they never gave us any indication he was capable of it, we just have to guess that maybe something happened in Iraq or something. And you're right the explanation was bad, but I don't think they were trying to go for a sub/dom thing. I think the idea was suppose to be that Zack was impressionable, and that Gormogon was able to convince him that he was doing something great and good. Basically that if you knew the way to talk to him Zack was easy to convince.