The scenes on Zondawl were filmed at a shopping centre in Guildford.
Director Viktors Ritelis didn't tell Paul Darrow and Glynis Barber where some of the mines had been placed. When running through the minefield, most of their surprised and frightened looks are genuine.
This is the last episode to feature Servalan.
Despite going to the trouble of decontaminating it here, the Scorpio crew quickly abandon and destroy Xenon Base in the following episode, Blake (1981).