In the opening 45 seconds of the movie, we are able to establish one of the films main characters.
As you can see, Tom Cruise's character Vincent is the main character. We can tell this because throughout this scene, Vincent is the man in focus. Even in the busy airport, Micheal Mann has used a shallow depth of field to focus on him during this busy time. During this opening scene, we can hear the diegetic sound of Vincents footsteps which makes him seem more bigger or powerful than everyone else. The way Vincent is dressed shows that he is a mysterious man as he is wearing a grey suit with sunglasses on which hide his face a bit creating a sense of mystery.
This part of the scene is completely different to when we get introduced to Jamie Foxx's character Max. When we meet Max, he is doing a crossword puzzle in a busy taxi business. We can tell he is a main character because the camera stays on him for quite a while. It is very noisy during this scene and so Max goes into his cab, when the door closes, the audience hears hardly anything as the sounds all become silent once the door closes. This could symbolise that the character Max feels isolated or the character could prefer being on his own rather in a loud and busy surrounding. We then realise that the character Max has an ambition as he has a picture of a island that he kisses and keeps in his taxi. This could be his home island and so giving him a reason for working.
These two different scenes in the opening sequence of Collateral show great contrast. In one scene we see a powerful mysterious character and on the other hand we have a isolated or peaceful character who feels comfortable when he is behind the wheels of his taxi. I think the director has done this not only to introduce the two main characters but also show how different there lives are to one another. This idea could be used in our opening sequence to help show a great contrast between two characters.