This was terrible. For 90 percent of the show you have no clue why Nelson and Crane would want to kill each other. Spoilers here. They were part of a government experiment to see if subliminal messages worked. Would the government really pit their best officers in a fight-to-the-death experiment? I could understand using prisoners, but top commanding officers?
There was another odd thing in the episode. Nelson reveals there's one more gun on the ship safely ensounced in his cabin, and where does Sharkey lock up Crane? In Nelson's cabin! This right after Nelson said the gun was there. And the gun never turns up.