While walking the ice cold wastes of the prison planet in his regular clothes, the Doctor seems quite unaffected by the cold. This was a trait shown by the Second Doctor in "The Tomb of the Cybermen", the Fourth Doctor in "The Seeds of Doom" and "The Hand of Fear", the Ninth Doctor in "The Unquiet Dead" and the Tenth Doctor in "Planet of the Ood", and an improvement over how the First Doctor responded to cold – not just subzero cold – in "The Space Museum".