Not on the same scale, but I've found having screwed up badly in the past helps me keep my calm in the present. My favorite example: about twenty years ago I accidentally played a note during a grand pause (the entire orchestra silent) in the first movement of Beethoven's Fifth. In concert, at Hill Auditorium. That's one of the worst musical mistakes possible, in the one piece of classical music almost everyone knows, in what is almost certainly the nicest concert hall I will ever get to play in.
Ever since then when getting ready for a concert where I'm not the soloist, I can just tell myself "What can I possibly do wrong that would be worse than that?" and the tension goes away.
Music performance is an interesting analogy. It is simply impossible to learn music without making mistakes. One of the things that separates amateurs from pros is the ability to recover from a mistake, failure or disruption. Regardless of how great things sound in a practice room, the goal is the performance.
Its funny, failure in front of an audience is rarely fatal, but a huge fear for many.
That's the interesting thing about the human brain and our reactions to things. When compared rationally what happened to you seems trivial. But in your brain it was the worse thing in the world on the scale of a true disaster. Reminds me of situations where one has a health scare or a hypochondria before knowing the true details of their illness. The feeling you get is as if you are headed toward death and others sometimes laugh at how out of proportion a reaction is to the evidence at hand.
In my experience adventure sports like mountaineering can provide a similar sense of perspective. Even if things are going well, it's clear that decisions can have real physical consequences.
Training programs like the National Outdoor Leadership School can be a good jump start into the leadership aspects of those sports.
