In the middle of the night, Captain Beatty, Montag, and the rest of the firemen stop at Montag's house. Captain Beatty now had an opportunity to burn down Montag's house for his "crimes" by keeping books now that Mildred and her friends ratted him out. After burning the house in an unforgivable way Captain Beatty and Montag have some conflict until it Captain Beatty said the word "Under arrest" and that's where Montag was so mad he grabbed to the flame thrower and burned Captain Beatty alive.
After committing murder, Montag knew what he needed to do., and so he grabbed the hidden books that weren't in the house and planted them into firemen's houses, and ran to Faber's house for his clothes to go to the river. Once he got to the river no one could go for him. Not the hound, not the helicopter, not even the police. He was just there floating down the river trying to forget his old life, down to the raildroad tracks.
Coming out of the water, Montag runs into these men along the railroad tracks just as Faber said he would by seeing the fire that got him thinking. He was introduced to a guy named granger where he and the rest of the men remembered books and were going to change society.