- Several bits of Fridge Brilliance and Fridge Horror come into play if you consider how child-Davros's encounter with the Doctor may have timey-wimeyly influenced his then-future actions:
The Doctor: Yes, you have got to decide that you're going to live. Survival is just a choice — choose it now...Tell me the name of the boy who is not going to die today!
- Down to the Daleks' Catchphrase "Exterminate" might be an effect of the Stable Time Loop. Davros heard the Doctor use it in the past, and the Daleks got it from him, but the Doctor used it because of the Daleks.
- Much as Clara may have given the Doctor his whole, "Fear makes companions of us all." ,the Doctor may well have given Davros his commitment to survival at all costs.
- Davros proves his memory of his initial confrontation with the Doctor by returning 12's sonic screwdriver. Here the Fridge Horror sets in when it's clearly been damaged, as the tip of the screwdriver resembles the eyestalk and laser in Dalek casing. Davros reverse-engineered some of the Doctor's designs, further tying into the Doctor's guilt in the Daleks' creation.
- After decades of fans, and even an occasional in-Verse character, making snarky remarks about Daleks' suction-cup manipulators, this episode may have actually come up with a justification for why Davros designed them that way in the first place. Most robotic appendages suited for handling objects ought, for practicality's sake, to resemble hands in some way ... but Davros, as a small child, found himself trapped and desperate in a field of hand-mines! Which means that, subconsciously, adult Davros still finds hands (or perhaps just artificial hands) to be scary, and so has convinced himself that suction cups are a "superior" option to the sort of limbs that would remind him of that trauma.
- Likewise, neither his Daleks' eyestalks nor his own artificial eye look much like real ones, because memory of the hand-mine field makes Eyes Do Not Belong There a really uncomfortable trope for Davros.
- The Doctor saved child-Davros by blasting away all the monsters with a Dalek gun, in just a few seconds. Could this be why Davros later picked that particular weapon to equip the Daleks with?
- Davros expresses admiration and pride in the Daleks, but is never seen actually talking to or directly commanding them. He's frequently been the leader of one side of a Dalek civil war, or never directly in charge due to being dead, or possessed by a split personality that thinks it's a Dalek. Here he describes his relationship to the Daleks as a father with pride towards his children for all their accomplishments well, what good father would keep ordering his grown-up children around when he already admires what they're achieving on their own?
- On a positive note, if anything was going to get Missy on the Doctor's side for real in the current conflict, Davros may just have accomplished it without actually planning to. To get killed by Daleks isn't anything unusual for a Time Lady, considering how many of them died that way in the war — and Missy has been exterminated by them before, when the Doctor was in his eighth incarnation — but to get killed by Daleks as collateral damage in a plot by a rival Doctor-Archenemy has got to be pretty darned embarrassing for the self-proclaimed Queen of Evil. So if Missy comes back in "The Witch's Familiar", and remembers what happened to her, she's going to be royally pissed at the shriveled-up little troll: destroying her civilization is one thing, but discarding her as irrelevant is another.
- What this episode does do is remind us WHY Davros created the Daleks- a centuries old war, with his people on the edge of extinction. The insanity is a by-product, not the reason.
- The No-Sell outcome of Missy's attempt to persuade the Daleks to let her live, because she'd be useful, becomes even more of a "serves you right" moment when you recall that Missy, herself, had dismissed Osgood's Can't Kill You, Still Need You argument just as casually in her last appearance.
- Related to this: why would the Daleks dismiss her claim that they would need a Time Lord/Lady to make full use of the TARDIS in their possession? Well, remember the Genesis Ark back in "Doomsday"—a piece of Gallifreyan technology which they used to release the Daleks trapped in the Time War? It wasn't activated by the Doctor, but by Mickey, a human time-traveller—because technology like these don't really discriminate. The Daleks are pretty much well-versed with Time Lord technology than we normally give them credit for, and so having a loose-cannon Time Lord like Missy as The Quisling is not a wise thing to do for them.
- Clara says of the Doctor, "He'll go all Scottish!" In the very next big scene, when Missy's declaring angrily "Noo, Ah've noht tourned goot!" her own Scottish accent becomes quite prominent. The Doctor regenerated into a Scot, and Missy followed his lead. It helps show how determined she is to bridge the gulf between them.
- Missy's Noodle Incident references from the Doctor's youth Fridgily demonstrate that, brilliant though she is, Missy doesn't necessarily know everything.
- She assumes Clara won't be able to tell which of the three references is a lie, but Clara (and the audience) know perfectly well that the Doctor's first incarnation was male: she and we saw him as a child in "Listen", and even heard two other Gallifreyans referring to him as a boy. Furthermore, girl is a human term and she and the Doctor are above that; they can be anything at any point if they so choose! — to say that the Doctor's sad crying was him being "girly" then she's correct. The Doctor later reveals that he lost the moon and didn't steal it, backing up the idea.
- It can also be interpreted that Missy doesn't know the Doctor as well as she thinks she does. Not only is the "girl" thing clearly a lie, but the Cloister Wars and the moon incident are brought up again in "Hell Bent", and the Doctor reveals that instead of stealing the moon and the President's wife, he lost the moon and stole the President's daughter, the other version being a story put out by the Shobogans. Two of the things Missy tells Clara are lies, and she doesn't even know it.
- She was lying about only one of the references being a lie, and thought Clara would believe that. Clearly, she doesn't know that Clara herself is a fantastic liar.
- The odds of the Doctor accidentally showing up on pre-Dalek Skaro, just in time to confront child Davros, seem mind-blowingly vast, even allowing for the TARDIS's long history of putting him in terrible situations where he's needed. But if you assume that he was lying about the bookshop, but rather, was messing around with the controls Clara made use of in "Listen", it makes perfect sense that a moment's distraction would bring him to the childhood of one of his longest-standing foes.
- Alternately, the TARDIS can aim herself a lot better than the Doctor can, and every time it's a Contrived Coincidence that the Doctor lands somewhere, it's the TARDIS landing herself exactly where and when the Doctor needs to be.
Fridge / Doctor Who S35 E1 "The Magician's Apprentice"