Was Tegan perhaps the only companion ever to have been driven crazy from her time in the TARDIS? I'm not sure if I recall this right but in her very final episode when she finally got back to Earth she just bolted and ran.
No, she wasn't crazy. She left because the Doctor's life (thanks in large part to Eric Saward) had gotten too crazy and sadistic, with far too high a body count. "My Aunt Vanessa said, when I became an air stewardess: 'If you stop enjoying it, give it up.' It's stopped being fun, Doctor. Goodbye."
Oh OK for all these years I kept thinking her time in the TARDIS had driven her crazy, especially Kinda.
Great question! IMHO, Adventures with scary extraterrestrials in completely extraterrestrial environments could drive a person crazy, and the time between televised stories has also been filled with so many novels and audio adventures that she just had no time to relax. It didn't help that the Mara toyed with her, took a nap, then revived a few stories later... or how the Eternals were traipsing through her mind without her consent. Except the Mara was sentient and consciously evil, the Eternals were just bored and found nothing better to get high on. It didn't help the number of times she was at gunpoint, kidnapped, threatened, under stress having to tell a Tereleptil asking her questions - no wonder she gets the Doctor's planet's detail wrong when trying to remember it. Indeed, given the basic trope, it's more natural for Tegan to leave having gone under excessive pressure than even Ian and Barbara as those two remained collected for the most part. Even under conditions where Ian should be a bit startled (though seeing the tender innards of a Dalek made up for it and he deals only with chemistry, not biological science), but isn't. Nope. After twice as many episodes of horrors Tegan had, they just stumble across a Dalek time machine and act like it's a box of chewing gum in the store's checkout aisle's impulse selection since when's the last time that section had anything useful that one's likely going to forget about?
She was one of the more excitable companions, for certain. If you haven't seen her classic episodes in a long time, I could see where you'd think "crazy". The Doctor: "I once spent a hell of a long time trying to get a gobby Australian to Heathrow airport." Clara Oswald: "What for?" The Doctor: "Search me.
I think it's the *opposite* - in my headcanon - Radiation emitted by the TARDIS impacts the human brain in such a way that it suppresses a normal sense of risk. For some reason, Teagan was immune and her reaction is entirely normal.
Well didn't the Doctor at one point threaten Ian and Barbara with throwing them out of the TARDIS while in flight?
She found it very stressful at the beginning but she was fine later. She did come back onto the Tardis after being left behind in Timeflight after all and even in her last story she runs back as if she'd changed her mind.
^True. While she may have changed her mind, I'm pretty sure that the Doctor hadn't. He was clearly so glad to be rid of her in "Time-Flight" and it's incredible to see his grimace as Nyssa invites her to rejoin them in "Arc of Infinity." It kinda seemed like the only reason why he added Turlough & Kameleon as companions was because he was hoping that they would annoy Tegan enough that she would leave because the 5th Doctor was too milquetoast to get rid of her himself. I kinda suspect that's why his next regeneration was so rude. The 5th Doctor was too easily pushed around, so he decided to become the kind of guy who wouldn't hesitate to tell people to f--k off if he wanted. That seems pretty irresponsible. When the doors opened while the TARDIS was in flight, it created a vortex that nearly sucked out everyone in "The Enemy of the World." And when the doors opened while landing, it made the TARDIS shrink in "Planet of Giants." I presume it was just an empty threat, like when he said he was going to spank Susan.
Every companion who travels with the Doc has their life threatened at some point or other. Tegan gave the show that one tinge of realism that at least ONE companion would finally say "enough of this- I don't need to be doing this". Not everyone is a fearless Highlander who knows how to use a knife.
There were other companions who weren't too keen on the danger that traveling with the Doctor put them in-- Ian, Barbara, Harry, Rory. I kinda wish that the show would go back to the format of "The Doctor & the companions are stuck together because he's so poor at piloting the TARDIS that he can't get them home even when he wants to." It seemed like maybe Season 11 was going to go in that direction given how things turned out at the end of "The Woman Who Fell to Earth," but alas....
https://tardis.fandom.com/wiki/The_Gathering_(audio_story) https://tardis.fandom.com/wiki/The_Harvest_(audio_story) https://tardis.fandom.com/wiki/The_Reaping_(audio_story) 3 part story where Tegan meets 5, and then 7, and then 6. The Cybermen are the big bad. All three stories take place on her 46th birthday. Tegan has cancer. If the Doctor wasn't going to cure her cancer, then partial cyberconversion would have.
I never listened to any of the audio stories, so I go by what was on TV. She had two run-ins with the Mara, which dominated her mind and left her quite disturbed. She was also very upset because friends she'd made either died or left (Adric died, as well as one of the female guest characters, Nyssa left, and people died in the episode in which she ultimately left). And of course the whole thing started when the Master killed her Auntie Vanessa. I would have been surprised if Tegan was not in need of psychiatric help when she finally left the Doctor and Turlough.