The Lazarus Experiment:
|–||Right at the start, Martha wonders "How did Tish end up on the news?" and pretty soon we find out why — she's head of PR for a major government-funded science project, with a big public launch event that evening — so, hardly surprising that it makes it onto that morning's TV news. And, to boot, Tish had even invited Martha to the event — but Martha still doesn't know why her sister could possibly be on the news?|
|–||When Tish delivers the guest list to Lazarus, she's holding the list by its edge with her fingers underneath as she lays it on the desk and starts turning round in order to leave. Then Lazarus schmoozes over and places his hand over hers — but her hand is suddenly resting on top of the paper instead.|
|–||During the experiment, when the machine starts overloading, the Doctor jumps over the counter to "save the day" — however, when the camera cuts to the wide shot of the machine still spinning, the Doctor can still be seen standing with Martha and co. as if nothing had happened! You can see him just behind the machine in the middle of the screen — he has his arms folded as he did just before everything started going Pete Tong.
[Admittedly it's a little hard to make out his face, but the Converse trainers are a dead giveaway!]
|–||Professor Lazarus staggering out of the machine suddenly "youthified" is all very exciting (if you haven't seen The Leisure Hive, that is), but the novelty of such an astonishing result seems to wear off pretty quickly for the party guests. After the initial applause, we cut to Lazarus getting his picture taken — presumably only a minute or two after the experiment has ended — but while there are a group of three women trying to get their photo taken with him, all the other guests have gone back to munching canapés, talking among themselves and ignoring Lazarus completely.
[What does it take to impress these people??]
|–||After the newly-young Lazarus discovers his appetite and starts wolfing down that platter of canapés, the Doctor comes over to confront him. While the camera cuts between the two of them talking, you can clearly see that from the reverse angle, Lazarus is chewing on his food, but when we cut to the front he's not. As there are several rapid cuts between the two, this is quite noticeable and jarring!|
|–||Whenever Professor Lazarus is addressing Letitia (Tish), the word 'Letitia' is clearly dubbed. The audio jars and his mouth looks to be saying something else. This is most painfully obvious when Lazarus returns to the party after killing Lady Thaw and he says Letitia's name twice in the space of 30 seconds.
[They must have changed her name at the last minute — wonder why?]
|–||When Martha decides to go back into the building to help the Doctor, Tish says "He was biding us time, Martha" — er, doesn't she mean "buying"?|
|–||There is no way that the half-a-dozen little gas taps the Doctor opens would accumulate enough gas in the room for such a huge explosion after only a minute or so.|
|–||OK, so imagine you're one of the partygoers trapped in the building — what do you do once Martha unlocks the door and you can get outside? Go home? Run for the hills? Make a bee-line to the nearest pub for a stiff drink? Well, apparently plenty of people think the best idea would be to just hang around outside on the steps, mere feet away from the unlocked door of a building with a rampaging monster inside it!
[OK, at least the Joneses had a good reason to hang around, since Leo was concussed and they wanted to keep an eye out for Martha. But what about all the others?]
|–||The Doctor's explanation of Lazarus's reactivated "dormant genes" is, in a word — pants. His extra limbs look very insectoid or crustacean, not to mention the scorpion-esque tail, so it's all clearly inspired by arthropod physiology. The problem is — humans evolved from a completely different lineage to arthropods. Or, to put it another way, we don't have dormant genes from our arthropod ancestors because none of our ancestors were arthropods!|
|–||When the Doctor and Martha are hiding in the Lazarus machine, the monster manages to turn it back on simply by pressing the red "start" button. But remember, earlier on the Doctor ripped out a big fat power cable when it started malfunctioning during the original experiment. Who repaired this and all the other damage to the machine in the meantime??|
|–||Also, the Doctor and Martha are in the machine for a long time — practically as long as Lazarus was himself during the original experiment! How come they aren't de-aged at all?
[Would Tennant have come out looking like William Hartnell??]
|–||When the Doctor is pacing around Lazarus as he recounts feeling defenceless during the Blitz, you can hear the noise of the Doctor's footsteps on the stone floor, as if he's wearing hard-soled shoes... when, as we've seen already in the episode, he's definitely wearing his usual Converse trainers.|
|–||The position of that red blanket over Lazarus's shoulders isn't consistent from shot to shot. It's particularly noticeable after the Doctor whispers to Martha about getting Lazarus into the bell tower — from the back, we see the top of the blanket is around the level of his shoulder blades, exposing the top of his back and both of his shoulders. Then we cut to the front view and the blanket is instantly covering both shoulders.|
|–||The Doctor's poignant monologue to Lazarus about "losing everyone that matters to you" is all very well, and he ends it with the pronouncement "Lazarus, the only certainty left is that you end up alone" but in context it makes little sense: with the technology Lazarus has invented, all your loved ones are going to be right there with you!
[That is, until you get overcome by hunger and eat each other!]
|–||There really is quite a lot of light coming through some of the cathedral windows (especially in the bell tower) considering it's the middle of the night!
[Yes, I suppose cathedrals are lit up at night, but hmmmmm nonetheless]
|–||The sounds coming from the pipe organ bear no relation to the notes that the Doctor actually plays on the keyboard.|
|–||The sudden way that Lazarus turns back to his old-aged self after he dies really jars. You could plausibly expect that to happen at the instant of death, or as a gradual change starting straight after death, but for it to happen seemingly instantaneously at least a minute after he dies...? That's just — weird.
[And yes, I appreciate that it's only the 47th least implausible thing in this episode, but still...]
|–||A boom mike makes an appearance in the final scene, when the Doc and Martha are outside the TARDIS: look out for it above the "Police Public Call Box" sign, just as Martha says "we've already said goodbye once today".|