Goof: In the victim's apartment, the camera focuses in on bare hands playing the piano. When the camera pans around the room, Sherlock can be seen at the piano playing. When he stops playing and looks up, he points out the blood evidence with a gloved hand. As he walks away from the piano, you can see that he is wearing gloves on both hands.
Watson: So that means you still might be the smartest person in the world.
Holmes: I would never suggest that.
Watson: Really? I think that's the first time I've ever heard you say anything remotely modest.
Holmes: It's not modesty. There's just no reliable way to test the hypothesis.
Holmes: Hard to picture what she does, isn't it? Sober companion. When I first heard that term, I couldn't imagine what it entailed, and I'm an addict. She practices quite a unique specialty, your daughter. She rebuilds lives from the ground up. You can measure her success in careers restored. In my case, criminals caught and in lives saved.
Mrs. Watson: Interesting. Never thought of it like that.
Holmes: Of course you haven't. You've raised a modest daughter. She would never say such a thing.
Watson: I put a lock code on here to prevent you from sending out texts.
Holmes: I was hired to breach The Leviathan. Do you think I wouldn't be able to get into your phone?
Erlich: If you know our work, you know that we introduced a new flagship product in 2009. The Leviathan.
Holmes: Yes. The safe that you marketed as impregnable. Did you people learn nothing from the Titanic?
Holmes: When you've eliminated the impossible, whatever remains, however improbable, is the truth.
Watson: And what's impossible here is that you couldn't break into the safe, but someone else could. In other worlds, you are the smartest man in the world.
Special billing was given to Aidan Quinn (and) for this episode.
Original International Air Dates:
Canada: December 13, 2012 on Global
United Kingdom: December 18, 2012 on Sky Living
The Netherlands: February 19, 2013 on SBS6
Czech Republic: March 12, 2013 on AXN
Germany: March 14, 2013 on SAT 1
Belgium: March 24, 2013 on VIER
The security company that hires Sherlock is called Casterly Rock Security. Casterly Rock is the name of the home of the Lannister family in George R. R. Martin's fantasy series A Song of Ice and Fire (August 1996 - present) and its television adaptation, Game of Thrones. Casterly Rock is described as being impregnable, rather like the Leviathan vault in this episode that the Casterly Rock Security company developed.