Factual error: In this episode, it is stated that the Moon's sudden increase in mass caused a devastating global high tide. The amount of the increase in mass is given as 1.3 billion tonnes. But the Moon has a mass of over 70,000,000,000 billion tonnes, or over 50 billion times the supposed increase. Such a negligible increase in mass, less than 0.000000002%, would have almost no effect on Earth's tides, let alone be devastating. (00:20:46)
Factual error: When Clara is watching the Earth through binoculars in order to see whether people left their lights on or off, the planet is rotating at an impossibly high speed. (00:36:15)
Factual error: Near the end of the episode, the full moon is shown in the daytime sky, well above the horizon. This is impossible, as any celestial body lit by the Sun has its full phase only when it is directly opposite the Sun; thus, a full Moon rises at sunset and sits high in the sky only during the night. For the Moon to be in the sky during the day as shown, it would have to be visibly of a phase other than full.
Suggested correction: The moon is not actually completely full. It's in a gibbous phase (opposite of a crescent), which can indeed be seen in the daytime.
Visible crew/equipment: On the Moon's surface, the camera and boom mic can be seen reflected on the visor of the astronaut as she talks to Clara.
Mummy on the Orient Express - S8-E8
Continuity mistake: When the Doctor offers Professor Moorhouse some jelly babies in a cigarette case, the position of the candy in the case changes between shots. (00:14:10)
Mummy on the Orient Express - S8-E8
Continuity mistake: When Clara tells Maisie that "Difficult people can make you feel all sorts of things", as she finishes the sentence the view cuts from a close-up of her to a wide shot, and the light and shadows cast onto her face change with it. (00:17:20)
Mummy on the Orient Express - S8-E8
Continuity mistake: When the Doctor takes a phone handset from the wall and sonics it before calling Clara, his grip on the sonic screwdriver changes between the wide shot and the close-up. (00:21:45)
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Mummy on the Orient Express - S8-E8
Continuity mistake: When the Doctor phones Clara and discovers she's trapped in the locked car with Maisie, his phone keeps switching hands. (00:21:55)
Factual error: After PC Forrest is killed by the Boneless, her nervous system is flattened and displayed on the wall, appearing as a mural. However, there are far too many nerves around where her liver would have been and not nearly enough around her brain.
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In the Forest of the Night - S8-E10
Continuity mistake: When Clara mentions worrying about a witch in a gingerbread house while she and the Doctor are searching for Maebh, the phones she is holding switch hands between shots. (00:20:11)
In the Forest of the Night - S8-E10
Continuity mistake: When Clara is looking at the drawing in Maebh's homework book while the Doctor tells her about the solar flare, her grip on the book changes between shots. (00:22:44)
Dark Water - S8-E11
Factual error: When Clara is speaking on the phone to Danny at the start of the episode her phone shows the call waiting screen for an incoming call from him. (00:02:25)
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Dark Water - S8-E11
Continuity mistake: When it's revealed that the dream patch is on Clara's hand, it's in her right palm. But in the wide shot when she's getting up as the Doctor explains the true nature of the patches, it's on her left hand instead. (00:13:21)
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Dark Water - S8-E11
Continuity mistake: As Clara nods and says "Fair enough" when she thinks the Doctor has told her to leave, her arms go from crossed to by her sides between the closeup and the wide shot. (00:14:29)
Dark Water - S8-E11
Plot hole: When the Doctor and Missy, the latest incarnation of the Master, meet for the first time, she passes herself off as an android. Only later in the episode, after seeing the Gallifreyan hard drive that she has been uploading human minds to, does the Doctor realise that she is a Time Lady, and he doesn't realise that she's the Master until she tells him in the episode's cliffhanger ending. The problem here is that over the show's long history, Time Lords have been shown to have the ability to recognize each other instantly, an ability that makes perfect sense given their powers of regeneration. Previously in the new series, it was even stated that Time Lords can psychically sense each other, an ability demonstrated on-screen in "The End of Time." In "Dark Water", this does not happen, at all. Now, the Master has a history of using technology to block his/her psychic signal before - the Archangel satellite network from Series 3. However, at no point in this episode or the next one, "Death in Heaven", does either the Doctor or the Master even mention such technology as being used, leaving the mystery of how the Doctor didn't recognize Missy as a Time Lady at the very least a rather glaring hole.
Continuity mistake: When the Cyberman in the office locates Clara hiding behind the desk, its gun arm goes from stretched out to bent between shots. (00:00:46)
Revealing mistake: During the scene at the beginning where people are taking pictures of themselves with the Cybermen, there are a few moments where the Cybermen's armour is revealed to be rubber when people touch it. (00:02:45)
Continuity mistake: During the early scene with the Cybermen outside St Paul's, when Missy pulls out her phone/disintegrator weapon and shows the Doctor pictures of the Cybermen going viral all over the planet, and when she prepares to take a picture of the two of them, her grip on the device, as well as which hand she's holding it in, keeps changing between shots. (00:03:00)
Continuity mistake: Missy's cameo brooch is unpinned and hanging askew when she vaporizes Osgood, but the brooch rights itself and is pinned properly when Missy steps on Osgood's eyeglasses. (00:23:00)
Continuity mistake: When Missy orders her Cybermen to blow up the plane and kill some Belgians, her control bracelet is missing from her wrist in one shot. (00:33:54)