I suck as a former medic in the USAF, I do just fine with people I don't know but the minute someone I know starts going over some surgery or trauma that involves pain or blood I'm done.
Wouldn't have made a good EMT or Fireman either, I stop at accidents and render first aid if I am right there when something happens. Stopped one time when bunch of kids were on the airport road near the terminal and I was dropping my wife off, they did something stupid and hit a guard rail ejecting 5 of them onto the road as the car hit and stopped.
I rendered assistance to one of the victims and others did as well. I stayed with an unconscious teen until an EMT arrived and took over. I remember looking to cross the road back to my car and then I woke up laying behind my car with an EMT over me asking if I was OK.
Other than my ego and a bit of roadrash on my forehead and nose where I face planted I was fine. Wife said she looked up when a EMT yelled there's another one across the road by that car, only to see my fat a$$ laying there.

Oh well, now I make sure I have my composure and don't stand too quickly around those events and I'm fine. This happened years ago and I haven't repeated the fainting since.