First, what is the title and author of the work to which you refer?
Answer:
I’d say it intensifies the speakers sense of urgency, because the modal verb must in this sense is used forcefully, as to imply there is little time and action must be taken due to this.
Biology,Economics,and Education.
C Oglesby, Merlin. Pugnacious Hummers See Red: How to Attract HummingBirds.