Doctor Who: 10 Huge Questions After Spyfall Part One
8. Has The TARDIS Really Never Been Breached Before?
The TARDIS is the Doctor’s safehouse. Its exterior walls and
doors are largely impenetrable. There have been several failed attempts by the
Doctor’s enemies to break into the blue box through explosives and the like. So
yes, the sight of one of the aliens bleeding through the doors would have been
new and disturbing to the Doctor.
That’s not to say the TARDIS is invulnerable and there is more than one way to get inside. It has become a danger from within, whether through a malfunction (The Edge of Destruction) or an alien presence. We’ve seen a range of threats over the years, from the almost comical (Sontarans on the loose in The Invasion of Time), to the psychologically disturbing (Amy’s Choice, The Doctor’s Wife, Journey to the Centre of the TARDIS).
The Master has enjoyed messing with the Doctor’s TARDIS in the past and we can speculate that his ‘ridiculous’ comment after being invited inside was more than a rouse. He once transformed her into a Paradox Machine (The Last of the Time Lords) and in Capaldi’s finale season, Missy even got to operate the TARDIS herself without the Doctor on-board (Empress of Mars). Whether or not he directly planned it, the Master will have been delighted at the TARDIS’s vulnerability to alien attack.