Twelfth DoctorOh. There it is. Silly old universe. The more I save it, the more it needs saving. It's a treadmill.
[the TARDIS makes soft chirping noises to the Doctor]
Twelfth DoctorYes, yes I know. They'll get it all wrong without me.
[pauses]
Twelfth DoctorWell... I suppose one more lifetime won't kill anyone. Well... except me.
[looks down at his hand, glowing with regeneration energy, then wearily looks back up at the TARDIS]
Twelfth DoctorYou wait a moment, Doctor. Let's get it right. I've got a few things to say to you. Basic stuff first: Never be cruel, never be cowardly, and never ever eat pears! Remember, hate is always foolish, but love is always wise. Always try to be nice, but never fail to be kind. Oh. And you mustn't tell anyone your name.
[smiles to himself]
Twelfth DoctorNo one would understand it, anyway! Except...
[cries out suddenly in pain, crumples to the ground, gasps for breath]
Twelfth DoctorExcept... children. Children can hear it sometimes, if their hearts are in the right place, and the stars are too. Children can hear your name. But nobody else.
First Doctor[the Twelfth Doctor holds up his right hand to the First Doctor, which is glowing with regeneration energy that he is suppressing]You are me? No! No!
Twelfth DoctorMadness? Well, you're an officer from World War One at the South Pole, being pursued by an alien through frozen time. Madness was never this good.
The Doctor[the 1st Doctor - talking in a bit 'dated' manner, tries to impress upon Bill Potts that the computer-generated lady is, after all, a woman]Oh, my dear, I - I hope it doesn't offend you, that I have had some experience with the, uh, 'fairer sex'.
[Twelfth Doctor is cringing at "himself", because he knows what's coming...]