This ties a couple of things together. Normally, when a person is celebrated for being a hero, they back off from the acclaim and say something like, "I just did what was necessary ".

Your piece implies that this reaction is useful to protect the ability to handle stress-- thinking about how heroic one is or ought to be is not the right place to put one's attention.

In addition, all the cultural stuff about wondering whether one is the right sort of person to do something heroic makes it less likely that people will react well under stress.

All this is what I've picked up from reasonably modern America-- if heroism is thought of differently in other cultures (I think there have been some where boasting was more acceptable), let me know.