This is the key moment, I think, in Peter Capaldi's first season as the Doctor. Notice how vulnerable he is, eve after the TARDIS traps the "Boneless." He starts off slowly, wistfully, thinking of how it could have been, and then, as he shrugs his jacket angrily into place:
I don't suppose it really matters now. You are monsters. That is the role you seem determined to play. So it seems I must play mine.The last line is a bit duff, but Capaldi sells it. More to the point, he has to work himself up to a classic Tennant or Smith style epic speech of epic-ness. This Doctor doesn't live there as easily as did his predecessors.
(The Doctor steps out of the Tardis. Clara, Risby and Fenton come down the ladder.)
DOCTOR: The man that stops the monsters. I'm sending you back to your own dimension. Who knows? Some of you may even survive the trip. And, if you do, remember this. You are not welcome here. This plane is protected. I am the Doctor.
(He turns, and Clara throws him the sonic screwdriver.)
DOCTOR: And I name you The Boneless.