I wonder about this. One soldier is not going to be enough. They kill this soldier's orders and the matter will die. It is only if other soldiers begin to refuse deployment based on the same argument that this is going to have the desired effect and snowball.
When it first happened, I though 'cover-up'. They're trying to keep the soldier quiet. But then... The Army is a little bit smarter than that. They know if one Joe gets away with something then all the other Joes will want to get away with it as well (think back to the Vietnam era- what would it have been like if kids had found a legal loophole to get out of deployment without having to flee to Canada). They must have known the domino effect this would surely create. They must have.
And surely the White House would have known this as well. So, I can't see the order to cancel the deployment order coming from there. Which brings you back to the military. I wonder if they did this on purpose, knowing what would happen?
I suspect if you could trace exactly where and from whom the rescinding order came from you could figure out a bit of this puzzle.