The Fourth Doctor's regeneration into the Fifth was a problematic one, and nearly failed, with the Doctor briefly taking on personality aspects from his four previous incarnations. After recovering in the fictional city Castrovalva, he continued his travels with Tegan Jovanka, Nyssa of Traken and Adric. After trips to the future and the past encountering villains such as Monarch and the Mara, the Fifth Doctor was confronted with tragedy when Adric died trying to stop a space freighter from crashing into prehistoric Earth (Earthshock).
When the Doctor met a new companion, an alien boy stranded on Earth by the name of Vislor Turlough, he did not know that Turlough had been commissioned by the Black Guardian to kill him. Soon after, Nyssa left to help cure Lazar's Disease on the space station Terminus. After meeting the entities known as Eternals racing in yacht-like spacecraft for the prize of "Enlightenment", Turlough broke free from the Black Guardian's influence, and continued to travel with the Doctor and Tegan. The Doctor met three of his previous incarnations when they were summoned to the Death Zone on Gallifrey by President Borusa, who was attempting to gain Rassilon's secret of immortality.
After further adventures in which the Doctor re-encountered old foes including the Silurians and the Sea Devils both Tegan and Turlough left the TARDIS. Tegan would find the death and violence they encountered on their travels too much to bear (Resurrection of the Daleks), and Turlough returned to his home planet of Trion.
Ultimately, the Fifth Doctor and his last companion Peri Brown were exposed to the drug spectrox in its deadly toxic raw form on Androzani Minor. With only one dose of the antidote available, he nobly sacrificed his own existence to save Peri, regenerating into the Sixth Doctor having expressed doubt (for the first time) that regeneration might not be possible.
Somewhere in his life (perhaps set after the events of Snakedance) he crashed his TARDIS into the TARDIS of the Tenth Doctor and consequently nearly opened a "Belgium sized" black hole because of the paradox caused. However the Tenth Doctor, remembering the event, knew how to stop it because he recalled watching himself correct the mistake when he was the Fifth Doctor. (Time Crash)
The Fifth Doctor was far more vulnerable, sensitive and reserved than his previous incarnations, and would often react to situations rather than initiate them. Unlike his more authoritative predecessors, he would treat his young companions as parts of a team, and would often willingly participate in situations under the leadership of someone else who had the strong command presence that he apparently lacked. However, the Fifth Doctor's boyish appearance, nervous energy and charm all hid the fact that he was a Time Lord of great age, compassion and experience.
This Doctor greatly abhorred violence and would often hesitate about taking matters into his own hands. For the first time indecision weighed seriously on the character, and it had its consequences. But this Doctor was also one of the most courageous of his incarnations. It was perhaps the awful realisation that his very existence begat violence, and the weight of companion Adric's death on his conscience, that led him to sacrifice his own existence to save his last companion, Peri.
The Fifth Doctor was the last to use the original sonic screwdriver, which was destroyed during The Visitation, although the Seventh and subsequent Doctors were later seen using new versions of the tool. In Time Crash, he declined to borrow the Tenth Doctor's sonic screwdriver, prompting the Tenth Doctor's sarcastic remark, "Oh no, of course, you mostly went hands free didn't you? It's like, 'Hey I'm the Doctor, I can save the universe using a kettle and some string.'"
The Fifth Doctor's chosen mode of dress was a variation of an Edwardian cricketer's uniform, and he was even seen to carry a cricket ball in one of his pockets (which saved his life in one adventure). He wore a cream-coloured frock coat, striped trousers, plimsoll shoes and occasionally a pair of spectacles. The Tenth Doctor, who inherited various traits from this incarnation such as spectacle use, revealed in Time Crash that the spectacles weren't actually needed to aid the Doctor's eyesight but were just for show to make him look clever (perhaps to counter his youthful appearance). The Fifth Doctor's costume also retained red question marks embroidered onto the collar which producer John Nather-Turner added to the Fourth Doctor's costume in 1980. The Fifth Doctor also displayed an unusually acute sense of taste in Planet of Fire, also inherited by the Tenth Doctor.
On his lapel, this Doctor wore a celery stalk. He claimed in The Caves of Androzani that the celery would turn purple in the presence of certain gases in the "Praxis" range to which he was allergic, although this allergy was not mentioned by any incarnations before or since. He said that if that happened, he would then eat the celery (explaining, "If nothing else, I'm sure it's good for my teeth"). In the same story, while attempting to revive a feverish Peri from Spectrox Toxemia, he had noted that celery was an "excellent restorative from where I come from", but that the human olfactory system was "comparatively feeble." The Tenth Doctor repeatedly poked fun at the celery in Time Crash, describing it as a "decorative vegetable".
Peter Davison stated in an interview on the DVD of Castrovalva that he thought the clothes he wore were far too "designed" and that he would have still kept them, but wanted to add some individual flair to them, as other actors portraying the Doctor have done in the past.Babelcolour Tribute
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