Between the loud gunshots, the bright flashes from said gunshots, and the chemicals from everything during that..... that baby grew up to become Hellen Keller.
Looks like the kind of film where 50% of their budget went on the licensing for this song. Edit: Of the other 50%, 25% went on the wages for all the extras that had to die on that stairwell, and the other 25% was the blanks for all the guns he shot