The narrator states that there weren't yellow-spotted lizards in Green Lake until after the lake dried up, but everyone knew about the "red-eyed monsters" in the hills. One afternoon, several men approached Sam. They said they were going rattlesnake hunting and wanted some of his "lizard juice." Sam gave each man two bottles of onion juice and instructed them as to when to drink it. He said that lizards don't like onion blood.
Finally the narrator solves the mystery: onions provided Stanley and Zero protection against the yellow-spotted lizards. This is another way that the natural world helped the boys, either inadvertently or on purpose, to best the Warden and complete their task.
Stanley and Zero sit in Ms. Morengo's backseat, the suitcase between them. Stanley admits he has no idea what's in it. Ms. Morengo explains that she's a patent attorney helping Stanley's father with his new invention, and she looked into the events that took place on the day the shoes were stolen. When she mentions interviewing Derrick Dunne, Stanley is surprised to still feel ashamed about the bullying he suffered. Zero admits that he stole the shoes, but Ms. Morengo says she didn't hear that.
When Derrick's bullying turns out to be one of the things that frees Stanley, it suggests that even though his cruelty was nonsensical and awful, it too happened for a reason—it becomes Stanley's alibi. Ms. Morengo's insistence that Zero not confess to the crime reinforces the idea that the formal justice system's provisions aren't enough to truly get justice; it takes human discretion to do that.
Ms. Morengo explains that Stanley's father invented a product to cure foot odor and passes the boys samples. Zero thinks it smells familiar, and Ms. Morengo says people think it's peaches. The boys fall asleep and it begins to rain at Green Lake.
Remember that Trout Walker had an incurable and smelly foot fungus; Stanley's father's invention then appears to be linked to the way in which Stanley atoned for Sam's death, as evidenced by the rain at Green Lake.