Someone who does a dangerous job is not necessarily a hero. The military is a great example. There are many guys who do brave things under fire, but that doesn't necessarily make them a hero. There's doing what you are ordered to do well and going above and beyond the call of duty. That is what separates the ordinary from the extraordinary. And the latter being more "heroic".
There is a fine line between self preservation under extreme duress and heroic acts. Anyone who's ever fired a shot in anger can tell you that when the bullets fly, you get the measure of the guys you are with, quickly. And to me, there are too many people that throw that word around without thinking. Audie Murphy- hero, guys who have dangerous jobs- just working guys. And there are professions where getting that label are very easy. Fireman, military members, police officers often get that label. They do happen to be professions that can demand heroic acts, but they are not necessarily heroes.
I'm a good example. I served in the USAF, fired my weapon many times, saw people die, etc. But I'm not a hero. I was just part of a team that were sent places to do dangerous jobs.
I once fixed a toy for my son. In his joy that it was fixed again he said "Daddy, you're my hero". While I was very flattered, I wasn't sure how to react to that.