Sentence 1: Tom tried to pet an obviously rabid dog. 
 Sentence 3: Tom didn't go for help, because he was too arrogant and smug 
 Sentence 4:  The rabies mutated and affected him quite badly 
 Sentence 5:  Tom started chasing people around and trying to bite them 
 Option 1: The dog bit him and infected him with disease. 
 Option 2: The dog got scared and ran off.