Continuity mistake: When the Doctor is restrained by two of the Editor's corpse minions, and the Editor demands to know who he is, the hand of the one holding the Doctor's right arm moves between his chest and shoulder several times. (00:30:50)
Continuity mistake: When Rose and Adam are in his workshop talking about aliens, during the exchange where she asks him about people who claim they've been in spaceships and he responds that he thinks they're nutters, Rose is poking around with her right hand at a storage shelf on the wall before moving her hand to a pile of boxes stacked on a table. When the scene cuts to a close-up of her, her hand has jumped back to the shelf. (00:12:40)
Continuity mistake: When Jackie is reporting the Doctor to the alien helpline, her grip on the cordless phone changes between shots. (00:29:55)
Continuity mistake: When Joseph Green (really Jacrassa Fel-Fotch Passameer-Day Slitheen) picks up the skin of Oliver Charles from the Cabinet table, he picks it up with his left hand in the first shot but is holding it with his right hand in the next. (00:32:30)
Continuity mistake: When Jackie is yelling at the Doctor about Rose's yearlong disappearance, in a shot facing her she turns her head to her right, then in a shot facing the Doctor she does it again. (00:04:00)
Continuity mistake: When the Doctor and Rose are talking on the roof, just before the spaceship appears, Rose's hair is blowing in the wind in shots facing the Doctor, but mostly still in shots facing her. (00:05:10)
Continuity mistake: During Harriet Jones' introduction, her grip on her ID card changes between shots. (00:12:25)
Continuity mistake: When the coroner is interrupted by a banging coming from the freezer while trying to do paperwork, she's shown turning around and standing up twice, in a close-up and the long shot. (00:19:20)
Continuity mistake: Early on, when Rose is talking to the Doctor about how amazing it is that they can visit days that only happened once, her hair moves from tucked behind her ear to covering it, then back to its first position. (00:05:00)
Continuity mistake: When Rose pulls out her phone and checks for a signal, she's holding it with two hands in the shots facing her, but only with one hand in the shots from behind her. (00:17:50)
Continuity mistake: When the Doctor is putting a new battery in Rose's phone, which hand he's holding it with keeps changing between shots. (00:18:00)
Continuity mistake: When the Doctor is standing in front of the giant whirring fanblades, just before he passes the first one, which side of his jacket is blowing away from his body changes between the wide shot and the close-up. (00:35:20)
Continuity mistake: After the Doctor freezes the Auton arm, its index and middle fingers are curled, while its ring and pinky fingers are straightened. When the Doctor and Rose are in the stairwell, most noticeable when they emerge at the bottom, the fingers of the arm are now all slightly curled.
Continuity mistake: Partway through the episode, there's a wide shot of London, with an undamaged Big Ben visible. The inciting incident of the previous episode was a spaceship crashing into the clock tower, severely damaging it. (00:25:40)
Continuity mistake: After the Doctor gives Rose instructions, he crosses his arms and leans against the TARDIS. In the close up, he does it again. (00:00:25)
Continuity mistake: The Doctor pulls the arm off Rose, deactivates it, and the fourth and fifth fingers are the last to stop moving. When the angle changes, the first two fingers are the last to stop.
Continuity mistake: When Suki goes to leave the lift on floor 500, her arms are by her sides, then suddenly both hands are gripping the strap on her bag. (00:14:00)
Continuity mistake: When Rose is telling Auton Mickey that she thinks they should stay away from the Doctor because he's dangerous, a lock of her hair in front of her face tucks itself behind her ear when the shot changes to a close-up. (00:24:42)
Continuity mistake: During Mickey's struggle with the plastic trash bin, the angles of sunlight and shadows keep changing between shots. (00:22:20 - 00:23:20)
Continuity mistake: The Auton in the red shirt is seen starting to come down the escalator, then at a quarter of the way down, then at the top again, just starting down. (00:38:22)
Chosen answer: 1) When Stephen Moffat took over he ignored a lot of what had been developed before (there is not in-universe answer). 2) It would have killed Rose, so the Doctor absorbed the energy. His body regenerated before the energy could do a significant amount of damage that would prevent regeneration.