The above post makes an excellent point. Johnny idolized Dally, comparing him to the "gallant" Southern gentleman in Gone With the Wind:
"'I bet they were cool ol' guys,' he said, his eyes glowing, after I had read the part about them riding into sure death because they were gallant" (76).
Later when Johnny and Ponyboy rush into the burning to church to save the children, Ponyboy catches Johnny grinning at him and observes:
"He wasn't scared either. That was the only time I can think of when I saw him without that defeated, suspicious look in his eyes. He looked like he was having the time of his life" (92).
Johnny loses his defeated look in the heat of the moment, because he for the first time in his life, he feels gallant, like the old Southern gentlemen in Gone With the Wind and like his idol, Dally. Johnny is used to being beat up by the Socs or his father, and usually being the one that has to be rescued. Now, he is the one doing the rescuing, and for Johnny, that feeling is empowering. Even though his life is in danger, Johnny Cade feels the rush that comes with bravery and selflessness, knowing that he is doing something to help others in need.
While Ponyboy was reading Gone With the Windto Johnny, Johnny makes the remark that the men are gallant, riding off into battle knowing that they will never return (and that Dally is somewhat like them). His view is somewhat changed after that and led to him deciding to run into the church and save the children. Johnny always saw Dally as a rolemodel and wanted to be like him and so saving the children was his way of being a hero. He knew he was doing the right thing no matter what the cost and so he had no reason to feel defeated or be mistrustful.