[s4e16] Silent Service Review

The story reaches its climax when the saboteur realizes Harm and Mac are onto him. He attempts to eliminate them to protect his hero persona, leading to a high-stakes confrontation in the cramped, pressurized corridors of the submarine before he is finally apprehended.

I can also tell you about:

: A crewman is killed when a high-pressure steam pipe fails—not due to age, but because it was precisely nicked with a scalpel. [S4E16] Silent Service