Like many in the medical profession, a Military Battle Surgeon is going to earn a pretty good living. The Armed Forces realize that these professionals could earn quite a bit of money in the private sector, so they pay well to keep 'em around. Of course, it is the government, so the pay is rather complicated.
To begin with, all Military Trauma Surgeons are relatively high-ranking, usually lieutenants or captains at the minimum. Pay will increase with experience and rank, but you can expect to start with a base salary somewhere in the $75k per year range, with higher ranking officials earning more like $120k. The military knows that many surgeons could earn more in a civilian practice (and are less likely to get shot at), so they tack on another 30 to 50 grand per year just to even the score.
Add to that the military benefits of housing allowances (which run from $1,000-$2,000 a month), great health benefits, part of your salary coming tax-free, and the possibility of military retirement pay if you put in the required time, and you are talking a pretty good chunk of cash. Plus, there's always the chance that you will save the life of some future billionaire, who will in turn shower you with wealth beyond your wildest dreams.