The Fisher King and The Doctor in “Before the Flood”

You will be a strong beacon. How many ghosts can I make of you?

You know, you've got a lot in common with the Tivolians. You'll both do anything to survive. They'll surrender to anyone. You will hijack other peoples' souls and turn them into electro-magnetic projections. That will to endure… that refusal to ever cease. It's extraordinary. And it makes a fella think! Because you know what? If all I have to do to survive is to tweak the future a bit, what's stopping me? Oh, yeah, yeah, yeah, yeah: the ripple effect. Maybe it will mean that the universe will be ruled by cats or something in the future. But the way I see it, even a ghastly future is better than no future at all! You robbed those people of their deaths; made them nothing more than a message in a bottle. You violated something more important than time: you bent the rules of life and death. So I am putting things straight! Here, now, this is where your story ends!