xkcd published a What If? video about the consequences of swimming in a nuclear fuel pool: https://youtu.be/EFRUL7vKdU8
It's entirely possible to build up skills allowing you to avoid using PPE, but every kid who sees you is being put at risk just so you can swing your dick around.
(That said, repeated head trauma does tend to thicken the skull, although any practical benefits are extraordinarily questionable.)
Yes, but you only need to mess up once and your skill doesn't save you from other people mistakes.
Humans don't have perfectly consistent attention, and by the time you think you have any skill like that your attention is even less consistent than before you started "practicing".