Theory:Doctor Who television discontinuity and plot holes/Dragonfire


 * It's not exactly an "error", in the sense that the production team intended it, but the literal cliffhanger at the end of part one is a big, ol' cheat. At the end of part one, the Doctor looks down an almost bottomless cliff of ice. But by the start of the next, the camera shifts to reveal that there's a handy little ledge, onto which Glitz is able to pull the Doctor.
 * A trick of perspective; it was likely there all along, but the ice cliff was jagged and made of tons of uniform-looking ice, which presumably would have made seeing the ledge that Glitz found trickier from the Doctor's perspective.


 * It's unclear why the Doctor, went out on the ledge.
 * This occurred because an important scene was removed which would have justified it.


 * Why hide the Dragonfire on the part of the planet that Kane can get to?
 * The "Dragon", which contains the Dragonfire, was Kane's jailer & also the guardian of the treasure, as the Doctor explains at the end of Part 2. Its weapons could easily have killed Kane. Since the arrangement kept Kane confined for 3000 years, it worked reasonably well.


 * Why does Kane kill his mercenaries, having gone to the trouble of collecting them?


 * Pure speculation, but he may have been intending to send them en masse into the tunnels and against the dragon, hoping by sheer force of (expendable) numbers to locate the Dragonfire and kill his gaoler. The Doctor's arrival thus rendered them largely superfluous, though Kane was at least able to use them to "clear the decks" before reactivating his spaceship.


 * Alternatively, the sole purpose of the mercenaries may indeed have been to have exterminated the entire community of Iceworld when it no longer served Kane's purposes to play host to the traders and their customers. Whilst he is imprisoned there, they enable him to amass / extort resources and recruits with a view to freeing himself, but once he is free and the ship is in flight, they are just unwanted ballast...


 * In a bizarre (and oft-repeated) piece of scripting, the word "mercenaries" is often used completely misleadingly, as Kane's frozen zombie army are most definitely slaves.
 * As shown when he tried to recruit Ace, Kane relied on them being foolish enough to take his money -- as mercenaries -- in order to lure them into becoming (in effect) his slaves.


 * That works alright for the likes of Ace and Belasz, who were given that much choice. Not so well for Glitz's unfortunate former crewmates, who were given none. While a person may "sell" themselves as a mercenary, figuratively speaking, when someone else does the selling the term is a shocking misnomer (though the irony may still have been intended).


 * It almost certainly was intended, as the story contains a fairly obvious critique of capitalism. Kane, business magnate and gangster, sees everyone as commodities, and to deal with him at all is to deal with the devil ... Belasz and Kracauer may believe themselves to be free in comparison to the zombies in the freezer, but events will prove them completely wrong.


 * Why does Kracauer stand still and let Kane kill him?
 * He is, to pardon the pun, frozen with fear.


 * Why does Stellar run around an ice planet in a dress?
 * There are 2 possibilities: First, although Stellar is described in this wiki as an Earth human, her species is never referred to on screen, so she may not be human & Iceworld may not seem cold to her species. (Kane looks human, too, but most of Iceworld is uncomfortably hot for him.) Second, even if she is human, individuals vary in their sensitivity to cold. She's also highly active most of the time, which would keep her warm.
 * The ice planet is also used as an intergalactic supermarket. There is presumably some kind of heating system which makes the parts we see, most of which are intended to be used by people, at a relatively comfortable temperature. Very few of the characters we see display any excessive signs of cold despite being dressed for, at most, mild and temperate conditions.


 * At the end, why doesn't Stellar's mother behave as if there's been a massacre (which there has)?
 * Stellar's mother had been searching for Stellar & was not present when the massacre occurred. By the end, when she finally finds Stellar, she has still not encountered anything to indicate that there has been a massacre -- no heaps of corpses, only an absence of the usual throng. She doesn't behave as if there's been a massacre because she doesn't know there has been.


 * How is it possible for the ice cream parlour's milkshakes to even exist? Wouldn't alcohol be more realistic, as milk would be frozen solid?
 * Since humans and humanoids are living there, the temperature cannot always be below freezing. The places where people live are covered and heated.  Much like a large shopping mall.  The ice cream parlour itself is warm inside, and they use a more or less standard milk shake machine.
 * This was also being broadcast on a science fiction show aimed in large part at children. As this is essentially a children's TV adaptation of Aliens, it was presumably decided by someone somewhere that showing the characters drinking alcohol either wouldn't really fit the vibe they were going for or would be considered inappropriate for their audience.


 * Considering Ace is now millions of years in the future from her own time, how does Glitz intend to get her home? Before she leaves Mel makes the obvious point that the Doctor would be the better one to bring Ace home yet neither he, Ace or Glitz seem to acknowledge this.
 * Well, the Doctor subsequently asks Ace to join him for exciting adventures around the universe, so this presumably counts as an acknowledgement. As for Glitz, since he clearly either isn't aware that Ace is time-displaced or doesn't care that much, he presumably considers taking Ace to Perivale in their "present" (i.e. at the time the events of the story are taking place) to be good enough. And Ace may not be aware that the TARDIS is also a time machine until the Doctor asks her to join him, and may also be a bit too polite/wary/insecure to essentially ask the Doctor to take her home.
 * Also, Ace very clearly doesn't want to go home. She is notably sullen and miserable about the prospect of returning to Perivale, and would much clearly rather have exciting adventures around the universe. She, at least, doesn't bring up the prospect of the Doctor returning her to Perivale because she's afraid he might, and when the Doctor instead makes it very clear that returning her to Perivale is quite low down on his list of priorities the matter becomes academic.


 * Stellar is meant to be a stand-in for Newt, the little girl from Aliens, right? But, Newt never wore a dress in Aliens, let alone one that's so impractical it shows Stellar's knickers when she crawls under a table in the cafe during the zombie attack.
 * She's a stand-in for Newt in a narrative sense, not necessarily a carbon character copy; that is, she basically fills the same narrative purpose (a cute little girl in a dangerous adventure), but it doesn't follow that in doing so she has to resemble Newt down to the last detail. Since Aliens also does not take place in an intergalactic supermarket and the Xenomorph didn't turn out to be a child-loving cyborg with a glowing crystal in its head, we can simply assume that some things were changed in translation either intentionally or because some of those involved didn't fully get the intended reference.


 * Why is Mel hell-bent on convincing Ace not to join forces with Kane when she has absolutely no idea who he is or what his motives are?
 * Because you don't have to look very hard at Kane or spend a lot of time with him to realise that whoever he is and whatever his motives are, he is clearly not a particularly benign or trustworthy individual. Especially since he orders Mel turned into a zombie halfway through his job pitch to Ace, which is hardly something that a particularly nice person offering someone a job in a position which is totally above board and legitimate would do.