Ask yourself simpler questions, like "If my friend has had too much to drink (and I haven't), would I drive them home from the party even if it meant going out of my way and maybe getting my car puked in?" That's a lot more likely to come up in real life...

I like to think I wouldn't just go out the window, but I'm not so sure. If he's bent on killing everyone he can and an officer was down, I'd probably grab his sidearm and shoot the gunman dead once said gunman had turned around (why is it that school gunmen tend to be lousy shots?) since odds are, I'd be a better shot than him. Of course, that's if my odds of success were high and my odds of window-escape were low or someone I really cared about was in danger in another classroom, for example. As for home invasion, he's getting a face full of shotgun, baseball bat, or steel pipe, depending on what part of the house I was in.

it is questionable. I would probably block the door if i heard shots, but adrenaline kicks in, so you could almost do anything. it is difficult to think in those types of situations.

This is a very important topic that Pat has brought up. The answer (I believe) is simple, and ageless. You do what needs to be done. It might be easy or hard, or unsavory, but you do what must be done. This doe not mean throw your life away, it means use your brains and quiet your misgivings; and act. Be decisive.

This so depends on context.

If it was my own family, then yes, no question. If it was a choice of who dies, I'd much rather me than them.

If it was my pupils, then quite possibly - they are "mine" after all, even the badly-behaved ones. There have been cases of armed attackers in British schools, so I do have a vague scheme of what to do in the event of an armed or violent intruder (routes I would take, doors I would lock (I carry master keys), things that I know would be available as weapons or defences). Even in a small school, there are a surprising number of hidey-holes and dead-ends to avoid or contain an armed intruder.

Strangers in the street? I really don't know.

How can anyone really tell what you could do under major stress.One time I was chase by a wild animal,and I ran faster than I have ever run in my life or thought that I could ever run.A person can do superhuman things when they need too.You can read of countless accounts of this in WW1 and WW2 by guys who never thought of themselves as being heros.Honestly I don't think I would be the first to stand,but you never know.

if i saw a gun and it was by me, then yes i would start fighting. but thats the only way.

Depends on the flight, fight, and freeze instincts. If it involved family, I would probably kick into "hero" mode. If not, more then likely flight or freeze. If I had a recording device, I'd record for some news shots!

Depends on what you mean by "life or death" (that is, whose), and what you mean by "hero". I ran out of a convenience store when I saw an elderly lady slip off the sidewalk onto the macadam and crash into the bumper of my car. I was so afraid she might have broken something, I would not let her get up right away, but made sure she was comfortable; until she was able to take inventory of aches and pains, etc. Is that heroic ? I don't think so, but she definitely appreciated my gesture. Was it life or death? It could have been, had she broken a vertebrate and then moved, but there was little risk on my part (except being sued, as happens sometimes). Did I think about this ? Not a thought....not about what might happen to me anyways. I was terribly afraid for the woman though.