Director of photography William Cronjager walked off the set when he heard of 'Peter Deuel''s death and stayed away when the show was re-filmed (he came back the following week to shoot the remaining episodes). Thus, in a few scenes where Hannibal Heyes' back is seen (scraps of footage of Deuel from behind, notably one scene where Heyes and Curry sit on adjacent beds talking), Cronjager's footage is used and the lighting of the scene changes notably from shot to shot.
Heyes has a mustache in the early scenes (as did Roger Davis in real life). After Davis's first day of filming, Universal executives thought the mustache was "sinister" and asked Davis to shave it. Because the episode was more or less filmed in sequence, Davis simply shaved the mustache off on camera and the "sinister" line was added to the script to explain why.