In the opening scene of Deja Vu, the setting and characters are established through the use of mise-en-scene. The use of slow motion and cameras angles builds suspense for us as the audience.
We also hear lots of different sounds, some are diagetic and some are non-diagetic.
Diagetic sounds are sounds or music which comes from within a scene. Non-diagetic is sound or music added, after filming has been completed.
The diagetic sounds are cause by cheering from the background crowd, this makes you feel as if something good is happening.

The positive tone of the happy families in the crowds is used to make a contrast when the tragedy hits.

Different types of edits are used to make the scene more intriguing, these are edits such as slow motion, jump cuts, and cross cutting!