ABC Group: Notes about the music, special effects and other production points

I think the factor that added more tension into the film is news announcement.
In the first half of the film (before the explosion), most of the background sound used in the film is the news announcement.(from 3.22-3.48) It gives sense of stress and the current situations in the film are also updated to audience. Additionally, date and some information are announced by texts. (from 5.46-4.48)