[[caption-width-right:350: [[SanitySlippage Clearly Susan's doing well this episode...]]]]
->''As we learn about each other, so we learn about ourselves.''
-->-- '''The Doctor''' begins to warm up to his companions, and vice versa

One of ''Doctor Who''[='s=] few {{Bottle Episode}}s, "The Edge of Destruction" (aka "Inside the Spaceship") is a two-part oddity wedged between two longer stories. Originally, the show was confirmed for four episodes (the opening story) to be reviewed up... then it was increased to 13, two more than "The Daleks" allowed for. Worse, there was no money for sets or extras. Although it's a filler episode, the story triggers some very important CharacterDevelopment for the Doctor and his friendship with Barbara.


The TARDIS lurches and everyone falls over, and when they get back up again, everyone's acting a bit odd. Weird stuff starts happening and the Doctor suspects there's an alien presence on board and gets very paranoid. He accuses Ian and Barbara of sabotage, drugs their cocoa, and is himself attacked by Susan running with scissors.

Turns out it's the TARDIS itself that's the problem. The Doctor hit the Fast Return Switch at the end of "[[Recap/DoctorWhoS1E2TheDaleks The Daleks]]", but it got stuck and the TARDIS has been whizzing back in time to the creation of the Universe... and, therefore, destruction. The weird stuff was the ship trying to warn its crew, who fix the problem (a faulty spring; lovely 1960s space technology) and go on their way. The Doctor apologises to Barbara for having been an utter git to her, and acknowledges that she saved their lives by realising the TARDIS was talking to them all along.

* AHouseDivided: The main characters are stuck in the TARDIS. Outside, the ship is about to tear itself apart and inside they're at each other's throats.
* TheAllegedCar: All this arc's problems are caused by a stuck button and broken spring. As the show reveals later, this module was a museum piece when the Doctor was still a young man.
* BillionsOfButtons: The console's (as iconic to ''Doctor Who'' as the blue police box) caused the actors to start [[http://static.tvtropes.org/pmwiki/pub/images/fast_return_9567.png labeling them.]]Incidentally, on the [=DVDs=] it turns out that nobody is sure who actually wrote it. Carole Ann Ford suggests it may have been her and Hartnell during rehearsal, but she isn't sure.
* BottleEpisode: The entire episode takes place in the T.A.R.D.I.S and its functions are shutting down, so a minimalist thing.
* BreakTheHaughty: Given that the Doctor was well into the "vicious" side of AntiHero in the first two stories, his behaviour here isn't very surprising. However, he reaches a new low upon threatening to throw Ian and Barbara out the TARDIS, something that could easily kill them. When the woman he threatens to kill not only gives him one hell of a WhatTheHellHero but also figures out the problem and saves the day, the Doctor is understandably humbled. Not only does this lead to his attitude improving but sets his moral compass in a more unambiguously good direction, something that determines the show's outlook to this day.
* CharacterDevelopment:
** This episode is a major stepping stone in having the Doctor's personality be more like what we know today rather than the {{Jerkass}}ery seen previously.
** This story begins developing the TARDIS, the first story to even hint at it being autonomous. Before this, it was mostly treated as any other time machine/spaceship; after this, writers and serials would hint more and more at it being alive, before finally being confirmed in "[[Recap/DoctorWhoS32E4TheDoctorsWife The Doctor's Wife]]".
* EarlyInstallmentWeirdness:
** Ian checks the Doctor's heartbeat and only hears a single beat. It's later established that the Doctor has two hearts.
** The Doctor scoffs at the idea that the TARDIS is sentient. The modern series in particular ran with this concept.
* EasyAmnesia: Temporary amnesia affects the crew as they forgot one another.
* EldritchLocation: The TARDIS itself becomes one. This was the first hint that the ship might be alive.
* EverybodyLives: No explosions and no stabbing means no death.
* FamilyUnfriendlyViolence: The scene in which a strung-out Susan threatens the other characters with a pair of scissors and ends up frenziedly stabbing a mattress (see the still photo above) sparked the first of the many controversies about whether ''Doctor Who'' was too violent/frightening.
* {{Foreshadowing}}: That Susan would be the most affected by the malfunctioning TARDIS makes a lot of sense after the latter revelation of her having above-average (even by Gallifreyan standards), but far from fully trained/controlled psychic abilities.
* MidairRepair: The Doctor has to fix the TARDIS before it hits the Big Bang and is destroyed.
* MindScrew: It's a baffling adventure inside the ship today.
* MinimalistCast: Only the four crewmembers and the TARDIS herself.
* MyGodWhatHaveIDone: The Doctor's been a bit of an ass until this point in time (and space), including threatening to bludgeon a caveman to death because he would've held the TARDIS crew up. But he has an epiphany at the end of this story on what a {{Jerkass}} he's been, and loosens up and becomes the Doctor we all love and know.
* NoAntagonist: Unless a faulty spring counts, there is no bad guy here.
* NoodleIncident: Susan recognises a photograph on the screen as Quinnis, a planet in the fourth universe where she and the Doctor nearly lost the TARDIS.
* [[NotHimself Not Themselves]]
* TheReasonYouSuckSpeech: Barbara gives the Doctor a big lecture about how he cares nothing about anyone else, thinks that he is the most important person in the universe, has no sense of right and wrong, just does whatever he wants to all the time even if it endangers other people, and is a horrible man, a terrible grandfather and genuinely deserves to be dead. This leaves him quite shaken, and the final part of the serial shows him apologising to her for his behaviour and admitting that her spirit in calling him out on it is the same thing that caused her to figure out what was wrong with the TARDIS and how to save them all. This is very important in giving him CharacterDevelopment.
* ResetButton: AKA The Fast Return Switch. This was the first and only time it was ever mentioned and it isn't working.
* SinkingShipScenario: This ship is malfunctioning and about to disintegrate.
* SlippingAMickey: The Doctor drugs Barbara and Ian's drinks to knock them out so he can investigate what is happening to the TARDIS without interference. Ian doesn't fall for it, however.
* WhatTheHellHero: Delivered by Barbara to the Doctor about his awful behavior.
* TheWorldIsJustAwesome: At the end, the Doctor delivers a truly beautiful speech on the creation of a solar system.
--> We're at the very beginning, the new start of a solar system. Outside, the atoms are rushing towards each other. Fusing, coagulating, until minute little collections of matter are created. And so the process goes on, and on until dust is formed. Dust then becomes solid entity. A new birth, of a sun and its planets.
* TheXOfY: The first[[note]]and second: the second episode is called "The Brink of Disaster", although two episodes of first story "[[Recap/DoctorWhoS1E1AnUnearthlyChild An Unearthly Child]]" were "The Cave of Skulls" and "The Forest of Fear"[[/note]] of a long, Long, LONG line of such titles.