Writing for adults often means just increasing the swearing - but find an alternative to swearing and you've probably got a better line.
Hitler: Thank you, whoever you are. I think you just saved my life. The Doctor: Believe me... It was an accident.
If it’s time to go, remember what you’re leaving. Remember the best.
We're all stories, in the end.
Do you know how you make someone into a Dalek? Subtract Love, add Anger.
I'd forgotten not all victories are about saving the universe.