This scene from DAWN OF THE DEAD (2004) is when they are in escaping from the zombies when they get into the mall.  The fast moving monsters are featured at the start of the scene running towards the survivors; fast moving monsters are used more often in the modern day horror film as they are scarier because they can keep up with you. In the scene leading up to the elevator there is a lot of non-direct screams and dialogue this is done to create a fear and panic.  Contrapuntal music is played once they are secured in the elevator, this goes against the mood of the scene and breaks the tension built up by the rush of the scene just before.