North by North West is a very popular film by the director Alfred Hitchcock. This film is a great example of the different things that a thriller has to include to make the audience completely focused on the plot of the story.. to keep them entertained and on edge. In a brief summary the film is about a man by the name of Roger Thornhill, played by the actor Cary Grant, is kidnapped by a group of people whom believe him .to be a man called Mr. Kaplan... throughout the film he tries to escape from the grasp of these people while also pursuing the real Mr. Kaplan whom  we come to know at the end does not even exist.
Below is a clip of the scene that begins this thrilling story...

At the beginning of the clip there is some non - diegetic sound which is the background music that is used to set the scene. the music used is classical and can be described as mysterious which is parallel to the actions of uncertainty that are being displayed by Roger Thornhill. When ''Mr Townsend'' enters the room the music fades and the there becomes a frequent camera cut to represent the tension that is building, The lack of sound also is a role player to create this unpredictable moment in the clip, this is carried on by the increasing voice level of roger thornhill as he tries to justify his belief that they have made a mistake till he opens the door and find one of the men that kidnapped him standing in his way. this sends a message to the audience that something unwarranted is going to happen to Mr Thornhill