It was originally decided that after Castrovalva, the Doctor would only have two companions, Adric and Tegan. As a result, the character of Nyssa was to be written out of the series at the end of this story. However, Peter Davison strongly opposed this move because he felt that Nyssa was the companion who was "most suited to his vision of the Doctor". Given this, John Nathan-Turner and the rest of the production team relented and Nyssa was retained. The story for the following serial Kinda was already developed with two companions and Nyssa was not featured in that narrative as written. Rather than a complete rewrite of Kinda to include Nyssa in the narrative, she remains absent much of that serial, said to be resting in the TARDIS. This was set up with Nyssa's collapse at the end of this story.
Nyssa's sudden fainting spell at the end of the story was a throwback to the style of serial transition often employed during the First Doctor era. In this case, the reason for Nyssa's sudden collapse is revealed at the start of Kinda: Part One (1982).
This episode was watched by 9.4 million viewers on its original transmission.
The doctor references bowling a "chinaman" which was cricket parlance for a left arm wrist spinner. The term is no longer generally used owing to its racial overtones.