Revealing mistake: When Blake hastily slaps at the oxygen vent control to close it, the knob breaks off, drops to the floor and bounces noisily away. (00:07:25)
Continuity mistake: When Avon is removing the gas canister from the ventilation system, an insert close-up of his hands shows that he's wearing a wedding ring. In the full shots, however, the ring isn't there. (00:09:50)
Plot hole: When he first shows the burned ison-crystal to Cally, Avon says that its loss will blind the Ortega's forward vision. Later, he assigns it a completely different function, saying it controls the hyperdrive instead. If this one little crystal is that vital to the ship's systems, why aren't these guys carrying a spare? (00:15:05 - 00:19:00)
Plot hole: Kendall stresses that only he can open the safe containing the valuable neutrotope. Yet later, he casually asks a crew member to retrieve it, with no mention of the safe's combination, making it a cinch for the villain to steal the goods and hand over an empty box. Naturally, no one bothers to look inside before Blake races off with the container. (00:16:30 - 00:21:05)
Other mistake: When Avon and Cally are taking off their gun belts to hand them to Blake, Avon accidentally clips himself in the chin with the protruding barrel of his gun. (00:22:00)
Visible crew/equipment: Just after Avon says that the numbers on the clipboard mean absolutely nothing, the boom shadow moves across the top of the metal safe set into the wall behind him. (00:41:30)
Plot hole: Avon delivers his summation of the crimes and the murderer's identity to the Ortega's crew - with his back turned to the guilty party the entire time. This gives the killer ample time to pull a gun on them. But it's also egregiously out of character for Avon, whose suspicious nature bordered on paranoia and would never have allowed him to be so careless. (00:42:25)
Other mistake: Just after Cally says that the pilot's death was "a misfortune," she stands and her chair scrapes noisily on the floor. The sound apparently startled Paul Darrow, causing the always-unflappable, nerves-of-steel Avon to flinch: the only time in all four seasons that he's ever seen, albeit briefly, to break character.