VALARIE: Tell me why then. Why did they have to die?

DOCTOR: So they and countless others wouldn’t die in agony later. So that the universe could heal.

VALARIE: Hmmm. If you were a monster, I’d leave. No, that’s a lie - er - I’d try and stop you. But you don’t sound like a monster.

DOCTOR: Thanks very much

VALARIE: Having to make a call like that. To save a universe that sick. Sounds like you’re a doctor.