People only look at the "form" of a Yogi/Monk but forget the "function" behind their approach to life. Yogis/Monks follow a framework/discipline/practice which they apply towards their philosophical goals usually some "supra-normal states of consciousness" whatever name they might give to it.
But you can take that same framework/discipline/practice and adapt it to your own chosen goal viz. Science/Business/Sports/Education etc. This is what i meant in my above comment. For example, the practices of Zen Buddhism derived from Mahayana Buddhism were co-opted by the Samurai class of Japan for the performance of their duties i.e killing others or to sacrifice their own lives! This has got nothing to do with Buddhist goals but everything to do with more prosaic survival goals. Both of them are using the common philosophical/psychological/physiological (breath+body) techniques but for different purposes.
One very well-known all-encompassing framework/discipline/practice is "Ashtanga Yoga of Patanjali" detailed in the "Yoga Sutras". Read my previous comment here to understand how you can adapt it for any goal - https://news.ycombinator.com/item?id=41538322
So when a Scientist focuses his entire energies (both mental and physical) that consumes his entire self to solve some problem he is sharing a characteristic of a Yogi for that time period. So does a student preparing for an exam, an engineer focused on solving a problem, a sportsman in the "flow state" etc.
You should now be able to see the parallels in the usage of the above framework by a submariner in the environment of a submarine. Outside of it he is no longer needed to practice that framework and thus can revert to his "ordinary civilian" self if he so chooses.
If you want to study more on the above see the excellent old classic; Yoga and Western Psychology: A Comparison by Geraldine Coster - https://archive.org/details/in.ernet.dli.2015.189086/mode/2u...