The panning shot which opens the story is actually of Rouen, France. The spire near the center is Rouen Cathedral, which for four years in the 1800s was the tallest building in the world. The same shot was also used to represent a different fictional nation in Time Bomb (1969)
During the scene in which Barney rescues Gemini and replaces him with an inflatable dummy, Tracey is in a nearby cell and must distract Captain Danko, as he has orders to kill Gemini. The script called for her to seem terrified to the point of tears. Lee Meriwether recalled her husband suffered a severe injury, and she had spent the entire night at the hospital. So with the script calling for her to be hysterical, she was already red-eyed due to staying up all night. However, the approach the director decided on was for her to act sexy and play with Danko. With the help of the make-up man she got through the scene, but thought she looked terrible in the dailies. But when she viewed the show on the air she was pleasantly surprised, as the editor had sharply honed the scene.
Ken Delo, who played Mr. Mechanico in the performance video viewed by Kamirov, was a regular vocalist on the "The Lawrence Welk Show" from 1969 to its end in 1982.
The show is greatly enhanced by the astonishing makeup worn by Leonard Nimoy in his impersonations of Zagov/Gemini. The cosmetics buried all traces of his visage. It also provided a first when at the close of the mission, he dramatically tears off the disguise in one complete take adding to the show's credibility.
With the premiership at stake, Kamirov never bothers to scrutinize and fully inspect the "machine", simply accepting the artificial articulated arm Paris is wearing as satisfactory proof.