In this episode we finally arrive at Shada itself, where the stakes are raised and the revelations come thick and fast. There are some wonderful plot twists in this episode, and also some classic Douglas Adams humour.
The Doctor's various put-downs as Skagra reveals his diabolical plans could have come straight from the pages of The Hitchhiker's Guide to the Galaxy, and we all had a good laugh with these scenes at the read-through.
Thankfully undetectable in the finished episode is the noise interference that gave us a few nightmares on the final afternoon of recording. Everything had been going like clockwork, and it even looked as if we might finish ahead of schedule, when our microphones started picking up the dull thump-thump-thump of amplified rock music.
All through the week we'd socialised with Massive Attack, who were mixing their new album 100th Window in the studio upstairs, and initially we thought it must be their playbacks coming through the ceiling. But the real culprit turned out to be a party in the house next door. Christchurch Studios boast state-of-the-art soundproofing, so you can only imagine how loud the party must have been.
As our luck would have it, the scene we were trying to record was a quiet one, in which the Doctor, Chris and K9 hide from the Krargs and then hear the familiar hum of a TARDIS. Whenever Paul said 'Shh! Listen!', all we could hear was the music - as though the Doctor were alerting Chris to the sound of a nearby Krarg discotheque.
After an hour or so of trying to work around the problem, the diplomatic studio manager succeeded in getting the racket next door turned down, and we re-recorded the offending scenes. So everything turned out fine in the end - apart from our hopes of finishing ahead of schedule, of course.