One, there should be plenty of uncertainty. If there is a failure in a seal on the main induction due to a bomb blast, the first you may hear of it might be as you sink.
Two, the sub does leak. Lights blink, all kinds of wierdness happen near crush depth. If the crush depth is 150ft due to previous damage, it does it at 150ft.
If you get bombed. GO HOME.
Course you also should never have been bombed by a Zero since they didn't carry bombs, but that's another thread
tater