It is also the final episode to have Moffat in charge as the executive producer, who also announced his decision to step down from the role after the special; his successor, encounter with the Cybermen, the First Doctor refuses to undergo his regeneration.
It is also the final episode to have Moffat in charge as the executive producer, who also announced his decision to step down from the role after the special; his successor, Chris Chibnall, is credited with writing the closing scene of the episode. At the South Pole, following his encounter with the Cybermen, the First Doctor refuses to undergo his regeneration.