The characters of Bele (Frank Gorshin) and Lokai (Lou Antonio) both wear shirts which are not pullovers but instead zip up the back. This was because makeup application with the shirts on would have soiled the shirts, and pulling shirts over their heads after the makeup was applied would have disturbed the makeup. Therefore makeup had to be applied first, including below the neckline of the mock turtlenecks they will be wearing. Then the shirts could be put on gently and laid over the made-up neck, and then zipped snugly up the back.
During the filming of Frank Gorshin and Lou Antonio's run sequences, Gorshin and Antonio collided with one another when neither actor knew the other was striding down opposite ends of the corridor. The camera crew hadn't warned them that their scenes were being shot simultaneously.
The episode's plot was a clear indictment of the discrimination and prejudice which was still rampant in the late 1960s by showcasing its complete absurdity, especially in light of the assassination of Martin Luther King less than a year prior, and just a few years after the Watts Riots and the events later depicted in the films Ghosts of Mississippi (1996), Malcolm X (1992) and Mississippi Burning (1988). The white/black and black/white makeup was also a rather obvious allegory to the tension that existed between many whites and blacks, especially in the Southern United States. However, many critics charged that this underlying message was considered much too obvious and heavy-handed, overshadowing what was otherwise excellent acting by Frank Gorshin and the series regulars.
The screenplay was based on a story by Lee Cronin, the pseudonym of Gene L. Coon. He used a pseudonym because he had left Paramount and was under contract with Universal, so he was not supposed to be working for Paramount as well.
Every time there is a "red alert", the camera quickly and repeatedly zooms in and out of a shot of the one of the many flashing, red warning lights which indicate the red alert. This camera effect, no doubt used to generate some interest in the episode, was only used in this episode.
The characters of Bele (Frank Gorshin) and Lokai (Lou Antonio) are depicted as wearing gloves all the time. This was not because it was a requirement of the script or character descriptions, but because the black and white makeup would have smudged and rubbed off every time their hands touched anything or any other character.
In the digitally enhanced version, the run in the hall sequences with Frank Gorshin and Lou Antonio's showing the archive stock footage of World War II-era London, England burning superimposed on the fleeing scenes of Lokai and Bele has been cut out.