Holmes: "I've decided to write the story down; as it was, not as John made it. Get it right, before I die."
Roger: "You're not going to die."
Holmes: "I'm 93."
Roger: "I had a great-uncle who lived to be 102."
Holmes: "Well done. That seals my fate. What are the odds that you would know two men who would live that long?"
Roger: "Well, I didn't actually know him."