Originally Posted by Mulett:
“He was offered "Time and the Rani" as his swansong, but according to Pip and Jane Baker was just too heartbroken to go back and film it. I imagine the end would have been different, with the 6th Doctor fatally injured in the giant explosion at the finale, perhaps sacrificing himself in place of Beyus. It does make me wonder which of the remaining season 24 stories could have been McCoy's first story instead, as none of them really have any gravitas.”
Yep, he didn't want to go back and film it because they only offered him one story to do it, to film a regeneration.
What I was talking about in my previous post was supposing Colin Baker had left at an end of a Season with a Regeneration of his own after playing the role for say four or five years. In other words, if he hadn't been sacked or McCoy hadn't been cast in his place.
I would imagine if he'd played the role for a few more years he would have mellowed further and become quite a lot more popular than he is now. Therefore I could see him having some seriously dramatic exit which maybe would cause him a lot of sadness, like in the way he grieved after Peri's supposed death.