I don't have time to train to the "professional" level on everything I'd like to, that's for sure. But I am trained to the "professional" level on some things, and it helps. Knowing deep in your bones that you can handle one set of adverse circumstance may be of help if you are facing something you're not as well trained for.
If you experience stressful situations, you will become better at dealing with that condition. I am sure I can be overwhelmed i the stress is great enough, my ability to function under stress has been helped considerably by extensive participation in volunteer search and rescue.
We could be called at unpredictable times, 24/7, although the probability of an operation was high on a late Sunday afternoon, especially if the weather was good. Operations varied in length from five minutes to more than two weeks. Participation was voluntary; one responded, if possible, but we all had real world commitments which sometimes interfered.
I learned a lot about effective cooperation, often, but not always, in a stressful environment, and about putting forth your best effort, often relying upon other members of the team to also do their best.
There is always a lot o discussion about what to put in a "bug out bag," and when i tune into those threads, I realize that I had been maintaining a BOB for many years. Packed with enough to keep me going unsupported for three days, with an extensive FAK and basic technical climbing gear, all adjusted for the variable seasons found in southern Arizona (One of my colleagues famously remarked that in summer our packs consisted of little more than giant water bottles). Today I have received CERT training, and a similar bag is packed and ready to go. I am older and slower now, and just a tad bit rusty, but if needed I expect the old habits to rise to the occasion.