A double stood in for Anthony Ainley during Kalid's transformation at the end of this episode so Ainley could prepare for the rest of the scene. The double nearly choked to death when his mouth and nose began to fill with the green fluid.
Although Adric had been killed in the previous episode, Matthew Waterhouse's contract extended into the filming of Time-Flight, the reason for Adric's illusory appearance in this episode. Waterhouse stated in an interview it was a good point to leave, as Time-Flight "was a terrible story".
This episode was watched by 8.5 million viewers on its original transmission.
For the role of Hayter the main guest star of the serial on the list were Maurice Denham, Peter Cushing, Bernard Archard, Michael Gough, Geoffrey Bayldon and John Carson plus William Lucas.