Darry reacted very strongly when Ponyboy came home late at the end of Chapter 3. What did Darry do?

In Chapter Three, Darry is up waiting for Ponyboy, and Soda is asleep on the sofa. Darry is "madder than I'd seen him in a long time," and he starts to yell at Ponyboy for falling asleep in the lot, saying, "Ponyboy, what on earth is the matter with you? Can't you use your head? You haven't even got a coat on." When Soda starts to stick up for Ponyboy, Darry yells at him, too. Ponyboy says, "You don't yell at him!" In response, "Darry wheeled around and slapped me so hard that it knocked me against the door." The brothers stand in silence, since nobody in their family had ever hit Ponyboy. Darry screams, "Pony, I didn't mean to!" as Ponyboy runs away, back to the lot, deciding to run away.