When crashing in a PS4 happens, it occurs to one game or application, it's very common because the game/application has corrupted in your PlayStation. You can try to restart the PlayStation and then the game. You can also try to update your PS4’s software to the latest version, which can help fix the bugs and glitches for you.
Probably not. The water will go in and make all the stuff wet like the motherboard and battery, my brother had an Apple watch and it had a small crack in the corner of the screen he went into the shower with it and it broke. You’re most likely gonna need to keep it away from water, just incase.