Were you thinking of the first option I gave you? If we do the GCA protecting the guy from terrorists plot line then maybe your guy can be more then meets the eye to have even more at stake. It will have small scale gunfights and espionage stuff. 
Roleplaying a world war could also be fun and we'd be like a smaller squad, possibly an elite team. A guy can get a special fighting permit if he is, for example, sterile anyways or perhaps is just too good to pass up so made the argument that he can be more useful as a "resource" by fighting. That sounds like an epic character. They wouldn't give in to that argument very easily though. It would take a rousing speech worthy of an academy award.