Susi is right, that was a very busy night. John gets kidnapped by Mycroft and meets Athena, Sherlock texts him, he gets back to Baker Street (stops on the way to get his gun), Sherlock shows him the suitcase and sends a text to the cabbie, they go out, chase down a taxi, return back home, where they find the police, while trying to figure out the case, the cabbie turns up, Sherlock follows him, they take a ride, John follows with some delay, shoots the cabbie, they leave the building and run into Mycroft and Athena, where John makes the “we met earlier” remark. No blooper, just a very packed storyline.