A Child's Way
He feels like a small child sometimes. A small child that does things not because it wants to or has to, but who is propelled by something deep inside, an urge to be different, an urge to break rules.
He knows what he does isn't right, but he can't stop himself and that scares him more than all the Daleks combined. He fears his behaviour will mean he will lose her. He has hurt her. His careless words lash out at her; he can see the pain in her eyes.
He feels like a small child, helpless to stop himself.