I think this is a modern response to the 'fight or flight reflex' we humans have been dealing with for millions of years - frightening situations have triggered a flight response for most of that time, we tend to hang around only when we assess that we can or must fight our way out of the situation. That fight or flight mechanism tends to keep us alive and propogating the species to live and fight another day. Everything from med school to wilderness first aid to combat training is intended to condition the person to stay and address the situation rather than run away. It runs counter to what our brains were originally programmed for, for the most part.
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I suppose "fight or flight" is part of it. The main point I was trying to make is that all too often people feel that they must react instantly. However, in most cases taking a bit of time to assess the whole situation leads to a better outcome. A very few situations really do require instant action, but most do not.
Using another analogy from first aid, one should try to avoid "Puddle Thinking". That's when you find someone with an obvious wound with a puddle of blood around it. You instantly jump in and do an awesome job of applying direct pressure on the wound. Sure enough, in a short time the bleeding completely stops

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But only then do you look up and notice that the guy (or gal) isn't breathing.......... 
In most cases, taking a brief moment to evaluate the whole situation is time well spent. You will have a much better set of priorities, you will think more clearly, and your overall response will be much better.