2.): there is NO real shockproof watch as they are all very, very delicate objects with very, very thin pivots and wheels.
ANY shock has an impact on the movement --> wheter you notice it immediately or later as they all add up.
I am not tired of repeating that it is a pure marketing tool from Rolex to claim that theire watches are sturdy, robust or in any other way immune to shocks.
My advice: no watch during exercise
The Nautilus is still a lovely peace and the water resistance is the "safety" argument here.
Same with the Sub: 300 m is safe for any water.
Regards
Moritz