On the flip side between where you can get out in a survival suit, where rescue submarines can get to, and places where the people tank will go crunch before you hit the bottom, pretty much everything is covered for USN submarines; it's a very safety conscious community.

https://en.wikipedia.org/wiki/Submarine_Escape_Immersion_Equ...

https://en.wikipedia.org/wiki/NATO_Submarine_Rescue_System