I don't know much about submarines, but I assume that you mean once the pressure hull is penetrated, the resulting pressure difference will quickly make short w

I don't know much about submarines, but I assume that you mean once the pressure hull is penetrated, the resulting pressure difference will quickly make short work of the hull. My point was that, if I could choose the failure mode, I wouldn't pick fail-all-at-once, if I could avoid it (for most things that bear load). If I could design/create a pressure hull that somehow didn't fail all at once, I think everyone would be happy?