* TechnologyMarchesOn: Sherlock sends simultaneous texts to the journalists and police officers in the press conference, with a snarky "Wrong!" to counter every statement Lestrade makes. This is framed as a mystery and technological prowess on Sherlock's part, which is rendered quite unimpressive when simultaneous text sending (via apps like Whatsapp or similar) became commonplace just a few years later.[[labelnote:Fun fact]] This episode aired in 2010. Whatsapp actually launched ''the previous year''.[[/labelnote]]
* ThrowItIn: According to the episode commentary, Sherlock kissing Mrs Hudson on the cheek wasn't scripted. Creator/BenedictCumberbatch had known Creator/UnaStubbs since he was very young, and it was his reaction on being able to work with someone who was like a mother to him.
* TroubledProduction: Originally this was shot as a 60-minute one-off TV movie. Its costs ballooned to an almost unheard-of one million pounds, and rumours flew that the Creator/{{BBC}} would pull the plug and leave it unaired. Instead, they asked Creator/MarkGatiss and Creator/StevenMoffat to turn the whole thing into a series pilot. That would entail making it longer. And they wrote a longer script. But they couldn't get the same cinematographer back, and didn't think the added scenes would be consistent with what they had already filmed. So ''they shot the whole thing over''.
** They had to do this, with many scenes taking place at night, outdoors, or both, during what turned out to be the coldest winter in Britain for three decades. Creator/MartinFreeman recalls standing in ice water once for several hours waiting to get a take done. One morning he fell while getting out of his ride to the set and broke his wrist, requiring that he shoot many of his scenes for the next several weeks with his arm temporarily liberated from its plaster cast. He was luckier than Creator/BenedictCumberbatch, though, whose persistent flu turned out to be life-threatening pneumonia, for which he was hospitalized.
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