Who calls the fire department to turn in Montag?
Actually, several people call Captain Beatty to turn in Montag for having books hidden. The first is the group of Mildred’s friends who Montag reads poetry to while they were all gathered together at his house. And, of course, Mildred, Montag’s wife turns him in as well. No explanation is given as to why Mildred sounds the alarm on Montag; perhaps Mildred is so indoctrinated by society that she feels she can’t live with Montag breaking the law. Their marriage is also loveless in many ways, and maybe Mildred sees this as a way out of their marriage. It is a betrayal that doesn’t really affect Montag emotionally; he is tired of Mildred’s fascination with the TV soap operas and her repetitive overdoses. The scene concludes with Montag burning down his own house, turning the flamethrower on Beatty, being partly injected by the mechanical hound, and escaping out of the city to join the hobos.