Sherlock and Taxi Driver in “Unfinished Business”

Sherlock

You risked your life four times... just to kill strangers? Why?

Time to play.

Sherlock

I am playing. This is my go. There's shaving foam behind your left ear, and no one's around to point it to you. There are traces of where it's happened before, so clearly you live alone - there's no one to tell you. But you have photographs of children. The children's mother has been cut out of the photograph - if she'd died, she's still be there. The photograph is old , but the frame is new. You think of your children, but you don't get to see them. Estranged father. She took the kids, but you still love them, and it still hurts. Oh, but there's more! Your clothes are freshly laundered, but everything you're wearing is at least three years old. Keeping up appearances, but not planning ahead. And here you are, on a kamikaze murder spree, what's that about? Ah! Three years ago, is that when they told you?

Told me what?

Sherlock

That you're a dead man walking.

So are you.

Sherlock

You don't have long. Am I right?

[taps his head] Aneurism - right in here. Any breath could be my last.

Sherlock

And because you're dying, you've just murdered four people.

I've outlived four people. That's the most fun you can have with an aneurism.