Other mistake: At the end of the episode, the evil Shan is texting with (most likely) Moriarity. She is sitting at a desk facing a wall and yet the laser targeting ray appears directly on her forehead, which could only come through a window directly opposite her.
Other mistake: Watson never orders, but somehow while in Angelo's, he has a full plate of pasta.
Chosen answer: That line of dialogue has never actually been spoken in any of the Sherlock episodes, during seasons 1-4. However, that line is written in someone's fan-fiction story online, where it's said by Sherlock and directed at Anderson.
Super Grover ★