Bart La Rue, who plays
the Imperial Announcer, had previously been the famous voice of the
Guardian of Forever in
"The City on the Edge of Forever".
Kirk blasts McCoy's and Spock's cell door open with a machine gun but when he opens the door there are no bullet marks on it.
During the first escape McCoy hits a guard in the chin. Despite the fact the guy's wearing a helmet with a metal chinguard, he goes down and McCoy's hand appears fine.
Ian Wolfe, who plays
Septimus, would later play Mr. Atoz in
"All Our Yesterdays".