Dally’s vehement opposition to Johnny Cade surrendering to the authorities stems from his deep-seated fear of the detrimental effects of the juvenile justice system on a vulnerable individual like Johnny. Having experienced the harsh realities of incarceration firsthand, Dally recognizes the potential for it to harden Johnny, stripping him of his inherent innocence and sensitivity. He anticipates that the prison environment would expose Johnny to violence and corruption, fundamentally altering his character in a negative way.
This concern is rooted in Dally’s own past experiences. He understands that institutions meant to rehabilitate often fail, instead perpetuating a cycle of crime and despair. Dally views Johnny as someone who is fundamentally different from the hardened criminals he knows. He sees the potential for good in Johnny, and believes that prison would crush that potential. His actions are motivated by a desire to protect Johnny from a fate he believes is worse than the consequences of remaining a fugitive.