As might have been expected from the boyish fifth Doctor, he sacrificed his own life so that his companion, Peri, might live. They had both contracted the fatal disease spectrox toxaemia and there was only enough of the antidote for one …
Where the fifth Doctor had been somewhat staid in his outlook, his only affectation being an eternally fresh stick of celery on his lapel, the sixth Doctor was positively ebullient. Perhaps because the regeneration was brought on by a fatal bodily poison, or perhaps because the Doctor was weakened by the illness, he initially suffered severely from post-regeneration trauma. As Peri discovered, he became unstable and violent, and attacked her physically as well as verbally. Moods of fatalistic melancholy gave way to poetic discourse and bewildering fits of bravado and cowardice. As he recovered from the regeneration, so these atypical seizures faded away, leaving a more mellow Doctor.
He could still be abrasive and brash but there was a human side to him also, one which he tended to keep hidden. However on occasion, when pondering on the destruction of Earth perhaps, or tenderly holding a dying friend, his sensitivity would come to the fore.
This Doctor was certainly not one to fade into the background, and his preferred mode of dress was a totally tasteless outfit comprising a gaudy coat of clashing colours, textures and patterns, green spats, patterned waistcoat and black and yellow striped trousers.
This incarnation of the Doctor never really got a chance to shine as no sooner had he started to enjoy his adventures than the Time Lords pulled him out of time to stand trial once more. It could be said that we never really got to know the sixth Doctor. 1998 David J Howe