THE MAD DOG. At the beginning of Chapter 10, Scout complains about her father being old and "feeble," but by the end of the day she discovers a hidden talent that makes her proud of her father. When a mad dog comes staggering down Scout's street, it is Atticus who is handed the rifle by Sheriff Tate to take down the dog.
In a fog, Jem and I watched our father take the gun and walk out into the middle of the street... In front of the Radley gate, Tim Johnson had made up what was left of his mind... He made two steps forward... We saw his body go rigid.
The rifle cracked. Tim Johnson leaped... He didn't know what hit him. (Chapter 10)
Although he had not shot a gun in 30 years, Atticus--the best shot in Maycomb County as a youth--had not lost his touch.
TAKING TOM'S CASE. Atticus didn't volunteer to defend Tom Robinson, but when the case was assigned to him, he accepted--knowing it could bring trouble for him and his family.
"You know, I'd hoped to get through life without a case of this kind, but John Taylor pointed at me and said 'You're It.'...
"But do you think I could face my children otherwise?" (Chapter 9)
THE LYNCH MOB. When Atticus learns that there may be trouble at the jail after Tom Robinson is transferred there, Atticus decides to stand watch by himself. When two carloads of men arrive, bent on taking and lynching Tom, Atticus boldly stands his ground.
"You know what we want," another man said. "Get away from the door, Mr. Finch."
"You can turn around and go home again, Arthur," Atticus said pleasantly. "Heck Tate's around somewhere."
"The hell he is... Called him off on a snipe hunt... Didn't you think about that, Mr. Finch?"
"Thought about it, but didn't believe it. Well then," my father's voice was still the same, "that changes things, doesn't it?"
"Do you really think so?" (Chapter 15)
It didn't change things for Atticus, who meant to defend Tom even at the risk of his own life.