That is, unfortunately, what makes the act heroic.
How many stories have ever been told, about the hero who forced his hypnotized orc henchmen to open all doors and cautiously shoved helpless farm animals down hallways in front of him to discover any deadly traps.
This presents a fascinating design quandary. People like to feel heroic. So if you design rules that support their heroism, you are by default making the act not heroic.
To be pedantic and exceptionally clear, if the odds are heavily in your favor, if the rules themselves support taking a 'risk', then it's not very risky. People doing a sure, safe, smart thing aren't heroic. They are just being rational.
Real heroism requires courage, which requires risk. It is a thing you do in spite of the fact that you know it won't turn out well. If you do know it will turn out well, where's the risk? Where's the bravery? Where's the heroism? </pedantry end!>
But if you like heroic behavior and you would like to encourage that in play, how would you go about it without devaluing it?
Making the character highly resistant to risk
This is the modern way of handling the situation. Make it easy to survive, reduce the risk associated with any individual threat, don't throw more at the players then they can handle at once. It can be fun, but it's low risk and certainly isn't heroic.
Character boon during heroic activitySubjectively deciding to reward players mechanically for heroic acts is an objectively terrible solution. Now, not only do they not know what their advantage is, they have to hoop-jump trying to guess what an individual will subjectively consider heroic. At this point, the value of their choices is minimized.
Granting players who engage in heroic type activities (volunteering to open doors, standing and holding off monsters while everyone else retreats) rewards, such as an increase in experience, bonuses or other mechanical advantages is a better solution, but still undermines heroism. One of the essential traits of heroic activity, is that it is engaged in without thought of reward. If you give out a 20% experience point bonus for opening doors and walking point, then you have a group of players all fighting for the honor. It does encourage more heroic behavior, but at the cost of reducing the value of heroism.
Reducing the penalties associated with heroic acts
Obviously the most common penalty is character death. This is probably the best solution - normally characters re-enter play at level one. Passing on a percentage of experience, or even a permanent boost or boon to a new character still has the pain of defeat (losing the character) but rewards the player by encouraging heroic play. Sadly this only has a great effect if the character actually dies.
Hack & Slash