@Legix
To be more specific he hired himself out as a Mercenary guard or he joined a local militia? If he was just a hired gun, he would have been more effectively a hired law man than a guard per se. I could see this happening in Siren System or one of the farther reaches of UOC space.
So the Surrender never actually happened. Ayana disappeared before the Surrender was supposed to be issued. The Black out caused a lot of chaos. The Tange Black Coats on Jiyuu started fighting the regular Peacekeepers for control of the government until the Lorath came in with bombardments and stabilized Jiyuu.
The SMX jacked up Jiyuu after that, some nasty radiation happened and Hanako rescued the other survivors of that fall out.
So depending on what settlement he was at- he could've very well fought SMX until he could escape. The main issue is that the surrender didn't actually happen. A lot of the confusion here this is part of the reason why my ongoing history project is to bring all of the facts together so it's easier to reference for new characters that were there when things went south.