Theory:Doctor Who television discontinuity and plot holes/Empress of Mars


 * We never do find out exactly why the Doctor, Bill and Nardole are at NASA in the first place. It is not because of the message being found (which would make the rest of the episode a flashback) as it's clearly indicated they went to Mars to investigate its origin.
 * It's not exactly a plot hole for the story, they likely were just wandering round as the Doctor always does when he's off on adventures.


 * Why does the TARDIS just abandon the Doctor and Bill on Mars? It's not like there's an outward force controlling it like the Silence once did or that it shifted into another dimension like in the Pirate episode.
 * Hostile Action Displacement System, perhaps?