Why was Dally afraid to talk to Darry

Dally knew that being the one to break the news about Johnny getting into trouble would earn him a beating.

I shook my head. Dally sighed. "Boy howdy, I ain't itchin' to be the one to tell Darry and get my head busted."

"Then don't tell him," I said. I hated to worry Sodapop, and would have liked to let him know I had gotten this far okay, but I didn't care if Darry worried himself gray-headed. I was too tired to tell myself I was being mean and unreasonable. I convinced myself it wouldn't be fair to make Dally tell him. Darry would beat him to death for giving us the money and the gun and getting us out of town.