1) The hound attacked Montag I don't know why but I think its because Montag killed Beatty and the firemen somehow told the dog to attack Montag but the hound died
2) Montag defended himself because he didn't want to die.
3) Montag then realized the Beatty had always wanted to die. Beatty wanted to die so badly that he made of fun of Montag and annoyed him while Montag was armed. He wanted Montag to kill him
4) Montag went to go get help.
5) I don't know what happened but he crossed the street really paranoid and he heard a car coming from 2 blocks away and he thought that for sure it was the cops.