Question for The Outsiders chacter3

Ponyboy ran away because Darry slapped him.

He should never yell at Soda. Nobody should ever holler at my brother. I exploded. "You don't yell at him!" I shouted. Darry wheeled around and slapped me so hard that it knocked me against the door.
Suddenly it was deathly quiet. We had all frozen. Nobody in my family had ever hit me. Nobody. Soda was wide-eyed. Darry looked at the palm of his hand where it had turned red and then looked back at me. His eyes were huge. "Ponyboy..."
I turned and ran out the door and down the street as fast as I could. Darry screamed, "Pony, I didn't mean to!" but I was at the lot by then and pretended I couldn't hear. I was running away. It was plain to me that Darry didn't want me around. And I wouldn't stay if he did. He wasn't ever going to hit me again