Physical Danger
Look at it this way: you may qualify for what is known as "hostile fire pay." It's a little something extra for working in an active combat zone, so physical danger is kind of inherent in the work of a military trauma surgeon. It takes a special type of person to focus on the well-being and safety of others in this type of environment.
Besides the "hostile fire" thing, any surgeon is going to be exposed to some potential dangers in their job, with sharp instruments and bodily fluids falling squarely in the job description.