The park is the place where Johnny and Ponyboy go to after Darry hits Ponyboy. The Socs appear there and confront the 2 boys for trying to give Cherry and Marcia a ride home. 3 of the Socs try to drown Ponyboy. Johnny gets out his switchblade in self-defense and kills Bob. The boys later flee from the park and go find Dallas.
Johnny and Pony in the park
Johnny pulls out his switchblade while the boys are drowning Ponyboy
Socs try to drown Ponyboy in the fountain.
After Johnny kills Bob
Johnny holding the bloody knife that was used to kill Bob