frankly, you seem to be hiding behind the wife and children. It's supposed to be the other way around.
I have learned over many years that the people who pat themselves on the back the hardest are always those that have the least to offer; and that those who are eager to pronounce that they are noble above some or all others tend to have overblown and inaccurate self images. Frankly people who blow their own horns are immediately suspect of being blowhards, or worse.
Military/Police/Firemen/EMT scenarios are not what this thread is about - it is about the ordinary Joe citizen/civilian with a ccw that stumbles onto a situation where he may be able to save a crime victim (not an accident victim) from harm, and what obligation does he owe a perfect stranger who hasn't taken the time and effort to arm himself to avoid being a victim. Without a very specific scenario all we can do is generalize.
Generally speaking if you find a situation where you can help someone without a significant risk, you of course help them. If there is risk - you should evaluate the risk and proceed or not based on that evaluation at the time. If it is likely that you will get killed in attempting to help a stranger, and you have a family of your own, then no, you should not take the chance of getting killed. The distance between go and no go is of course a gray area that can not be defined in general terms. Those of you who say you will help anyone at any time at any cost ~ I simply don't believe you.
Of course if you have a death wish and don't care a flip what happens to your own family, then go ahead and jump into any situation you find without evaluating first, the gene pool could use a cleaning now and then.