I'd take a bullet for someone I cared about, and for any child. I'd perform CPR without hesitation and probably would do so even if I didn't have a breathing barrier (yuk).
I've done CPR for real once.
I was the second person on scene; the first person had been doing it incorrectly (she hadn't tilted the head right, so she had been filling the victim's stomach with air). The victim puked; I cleaned out her mouth and kept administering CPR.
Actually, I didn't even think to get grossed out until afterward.
I think most of you don't understand the sheer gripping horror of these types of situations, there are no real heroes in the real world, and certainly no glamor in these types of situations.
for a soldier to get shot at for the first time, no matter how much training he got, the shock is devastating, running into a burning building is the same, so much more for people with no training as the men in the fire department, take a look at the photos of the American men of the fire department in Sept 11, no matter how tough they may seem, or how much experience they have, these men were broken.
I've never been in battle, but I've been marshalling long enough now that I don't automatically run away or freeze when an out-of-control car's coming at me. Instead, I can actually clearly (but quickly!) evaluate the situation and decide whether I need to run, duck behind a wall, or what-have-you.
I find that I'm okay in emergency situations... as long as I'm busy.
For instance, a few years back, I was the safety marshal for a bad emergency call: two little open wheelers had locked themselves together and slid into the wall. Unfortunately, because of the way they were stuck together, when they impacted the wall, the nose of the one car punctured through the side of the other car and the driver was seriously injured.
I was the first marshal on scene, and at the time, I did what I needed to do without freaking out. However, once race medical arrived on scene, I didn't have anything to do but get out of the way while they worked. It was only then that everything came rushing in at me and I felt overwhelmed.