Listen up buddy.
If you're out and about with infantry don't let anyone see you're medical personnel. They'll shoot you right after the guy with the DMR/LMG. Get rid of any stupid patches they give you and keep your shit bundled up just like everyone else's.
If you're humanitarian and they bring a native in with a decent cut right under his ribs and his tongue cut out he's a living bomb.
If you're dealing with US military don't take shit from them, especially marines. They'll walk all over you if you don't lay down the law. You own them, and if they so much as slap you they're in the deepest of all shit.
If you have the misfortune of working on Muslim "soldiers" don't put it past them to spit in your eye and give you every STD ever discovered and then some. They're typically loaded with them and think every non-Muslim dude is an evil capitalist pigdograt. Keep your mask and goggles on. Don't have either? Get some, soldiers always have eyepro and all cloth is a mask with effort.
Good luck.