He didn't want to go.
He had visited them all and knew that they were all alright. All doing good. He accepted that happily.
But that he had to go was a price he considered too heavy. He was a unique being. Yes, his memories and little bits of him would go on forever, but the core of him - that cool, suited and conversed, babbling, gabbling, mile a minute man that he was... would simply cease to be.
He knew he had no choice, that death, that inevitable occurrence, would claim this body, and he would be reborn as a new man. But he didn't have to accept it. He would not go quietly into the night. He would not vanish without a fight.
Quoting movies. He did that.
And it was cool.
And so he was born, born in fire: his past self burning his home and saying, "I will be remembered".
"You know, next time I'll just leave a note," the Eleventh Doctor said, pushing another button in a desperate attempt to stabilise. He flicked another switch, and the TARDIS bucked, nearly throwing him out of the door...