- Creator Backlash: Mark Strickson thought the leper colony idea was sick, while Peter Davison felt it didn't go anywhere.
- Enforced Method Acting: Sarah Sutton cried real tears filming her departure.
- Fan Nickname: The Garm is known to certain fans as the "Big Bang Dog".
- Pop Culture Urban Legends: It was rumoured that this story was supposed to see the return of the Ice Warriors. These turned out to be false.
- Throw It In!: Originally, the Doctor and Nyssa were supposed to shake hands as they parted, but Peter Davison and Sarah Sutton decided that he should kiss her on the cheek instead.
- Troubled Production: The production was fraught with technical difficulties, including problems with costumes, delays due to electrical problems, and a mis-built set. The result was that some scenes had to be recorded on improperly-lit sets, production ran seriously late, and several scenes were taped hastily, much to Peter Davison's frustration.
- An industrial dispute between the BBC and the electricians' union resulted in a major reorganisation of shooting schedules. As a result, the crew had to work against the clock to complete the story.
- Miscommunication with Rod Vass of freelance props firm Imagineering led him to believe that the Vanir armour he was asked to fabricate would be purely decorative. He was therefore shocked to learn upon delivery that they would be required for combat. The costumes proved to be extremely noisy when involved in vigorous activity, and costly refurbishing was required to address the problem.
- Because the first episode underran, Eric Saward asked Stephen Gallagher to to provide two new one-minute scenes. Unfortunately, Gallagher misinterpreted the request and instead extended several existing scenes to fill out two minutes' worth of material. Consequently, Gallagher's amendments were discarded.
- The first day of filming was plagued with problems. A power failure resulted in a two-hour delay. When the crew was finally ready to go, Mary Ridge discovered that one set had been erected off its marks, incurring a further stoppage. Then, John Nathan-Turner was forced to call a halt to the recording of scenes involving the interior of the TARDIS console because the correct circuity was missing. This meant that Ridge had to record sequences on other sets which were not yet properly lit. Later, it was learned that neither of the drone robot props had been tested before being brought into the studio, and indeed only one of them was found to work correctly. Despite all of these disruptions, Ridge was able to complete almost all of the scenes set within the TARDIS and the adjoining liner corridor.
- Many scenes were rushed through with only one take and little to no rehearsal, as Ridge had never once exceeded her allotted shooting schedule in her career, and had no intention of losing that record. Which, unfortunately, she did anyway after the various other problems proved too much for to recover from, forcing the team to schedule another couple of days of filming the following week... right after Sarah Sutton's farewell party.
- Wag the Director: The pilot had originally been dressed with cobwebs. Peter Davison objected, observing that he was not meant to be dead but simply moving very slowly, and Mary Ridge accordingly ordered them removed.
- What Could Have Been: Martin Jarvis, Patrick Stewart and David Warner were considered for Valgard.
Trivia / Doctor Who S20 E4 "Terminus"