 During production, director Douglas Mackinnon intended to have the episode's climactic scene in the TARDIS show the moveable column in the centre console move up and down much more rapidly than normal.However, when attempting to accomplish this, Mackinnon ended up breaking the prop, which took thirty minutes to repair.When interviewed on "Friday Night with Jonathan Ross", Catherine Tate stated that she had been filming alongside ten actors playing Sontarans for two weeks before she realised that there were actors inside the Sontaran costumes.