Sherlock Clip Analysis

Shots and resulting effects

Clip used

0:18 Zoom: Camera zooms in on Watson's bomb vest, with the music signaling the reveal.
Effectively shows the stakes at hand as his partner's life is put on the line, starting the dramatic and tense driven situation.

0:44 - 0:49 Jump cuts and Music/Editing: A close-up of the bomb vest is shown as Sherlock essentially saves Watson, the music, however, stays tense as Moriarty states that they aren't allowed to leave.
Effectively raises tensions as Sherlock is put at risk at 0:55 (Realising that Moriarty's men have guns aimed at him).

1:14 Close up and Reaction shots: Sherlock begins to take aim.
This close up raises tension dramatically as the audience is left to see what Sherlock intends to do, also providing reaction shots of each character as he begins to piece together what to do.

1:23 Point of view (Sherlocks): This shows us Sherlock's intentions as he lowers his gun to the vest that earlier put his friend's life at risk, allowing us to piece together the situation at hand.

1:40 - 1:60 Music/Editing and Reaction shots: Comedic sound relief is played as the music changes to Moriarty's  ringtone (Stayin' alive By Bee Gees). Reaction shots follow, showing a slightly annoyed Moriarty.
The close-ups now are distanced shots compared to before, relieving the tension felt before, yet still reminding us that Sherlock's life is still very much in danger (Still in the enemies sights, with Sherlock also still aiming at the vest)

2:06 Reaction shot: This adds to the comedic effect from before, still showing him in danger which likely goes unnoticed to the amused audience.

2:11 Editing/Music, Long shot and Reaction shots: All amusement is gone as the tense music comes sharply again as Moriarty snaps at the other person on the phone before threatening him in a very cruel manner.
The reaction shots that follow show more seriousness, with both being startled by his sudden and sharp words. This shows that the situation is noticeably tense again with comedic relief gone.

2:52 Long shot of Moriarty's dramatic exit: Effectively establishes the tension as the men still aim at Sherlock, right till the point where Moriarty signals them off.

My comments
Before the 1:40 mark, the atmosphere is set up as a very tense and dramatic one, resorting to extreme close-ups of Watson and Sherlock (Mainly Watson, with his face taking up the whole screen in his scenes). This is used to show the reaction of the 3 present main characters (Obviously excluding the Gunmen), creating a more dramatic situation as no actions are rushed and are dragged out for the purpose of being dramatic.
A close-up/Reaction shot is also used on Sherlock effectively to show his trail of thought, with the Pov shots to connect the dots and help the audience understand the intent of his actions.
The atmosphere is also rather unusual and dramatic, having the confrontation of Moriarty going down around a vacant and lightly lit pool, not going for a dramatic and cliche setting of somewhere dark as the situation surely is (Gotham for example, with most shots representing the town as a dark place, obviously being a place of crime etc). The setting is also plot perfect and interesting, with the bleachers above allowing Moriarty's men to take aim and provide overwatch.
At the 1:40 mark, the very tense and dramatic music seamlessly transitions perfectly to a comedic and amusing ringtone that breaks the audience away from the moment, even though they are still very much in danger (Moriarty's men are still aiming at Sherlock, as he is still aiming at the vest which could very much harm Moriarty). This essentially gives the audience a sound break which blinds them from the visual and very threatening nature of the situation that is still there. This adds to the sudden change in Music and Mood as Moriarty once again becomes excessively aggressive, taking the viewers once again almost by shock as the tensity is realized by the audience, growing more and more until Moriarty exits and signals for his men to do the same, leaving Sherlock unscathed.

The music was key to this shift in mood and is seen in many other shows that show a different take on it, with Lost doing something similar music wise in Season 2 Episode 1 (Except here it is done in the opposite way, with it starting in a relaxed tone unlike Sherlock did)

Thank you for reading my analysis!
Feel free to share your thoughts in the comments below.