As the credits roll, you hear a voiceover from a BBC guy saying: "The thing is with Sherlock, you have to watch right to the very end of the credits, or you will miss something." After the credits are finished, you get a glimpse of another British Original Drama (I don't know what it's called) featuring sledges and musketeer-like people. And I would swear that it is Andrew Scott saying 'miss me' during this very short trailer, just before a knife is thrown.