HE generally is. He won't be able to do anything complicated medical-wise, but he can stabilise until someone else shows up.

I like to see Mack as a jack-of-all-trades. You want something blown up? He's there with C4. Someone sniped? Give him ten minutes and a good tailwind. A non-lethal distraction? There'll be a ten-car pileup down the road in five minutes.