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Montag has committed murder by killing Captain Beatty with his flamethrower. His wife had already turned him in and left him. He knows there is no way to survive in the city, his name and face are all over the television, and the mechanical hounds will soon be turned loose to hunt him down, so he has to leave the city altogether.
He stops at Faber's house first, almost foolishly, and gets some advice as to who to look for. He manages to throw off the hounds enough to make it to the river and out of town just before the war starts and the city is destroyed. There he finds other refugee intellectuals in the same boat as he.