Trivia: While shooting an early episode, Mark Slade fell from his horse and suffered a painful bruise when he landed very hard on the gun at his hip. After much pleading, he convinced the producers and the prop dept. to make a replica pistol out of rubber. Replaced by the real one only when it actually had to be fired, the fake gun remained in Blue Boy's holster for the rest of the show's run.
Trivia: This episode was not shown in the initial U.S. airing of "The Prisoner" on CBS. There was speculation that its pacifist, anti-violence moral might have been construed as a Vietnam War protest, but the network's reason for censoring the episode has never been disclosed.
Trivia: When the Captain Scarlet series was sold to TV broadcasters, ITC (who had backed and then marketed the series) issued a "recommended broadcast order". This was not always the same order as the episodes had been made. Episodes 1 to 4 were made and broadcast "in sequence", but from episode 5 this no longer applied. Episode 11 ("Avalanche") was the 5th to be broadcast, swapping places with the episode "Point 783" which was the 5th to be made, but the 11th to be broadcast.
Trivia: In this episode, David Vincent reveals he has a friend in the C.I.A. named Jack Bryan, similar to Tom Clancy's Jack Ryan.
Trivia: In this episode, the murder victim's name is given as Reiko Hashimoto, and at one point, Gannon shows Friday a couple of photographs of her. Reiko Hashimoto was the maiden name of Reiko Douglas, the wife of comedy writer, author, and perennial talk show guest Jack Douglas, and the photographs used are of her.