How does the author use foreshadowing in The Truest Pleasure?

In Chapter Twelve, when Ginny visits the brush arbor meeting, she wonders if the Gibson boys, who stand outside with their guns, have been converted. On the surface, when the Gibson boys begin shooting into the tent, the initial symbolism of the act is that this extreme religion is dangerous in Ginny's life. As the novel progresses, however, this scene is extreme foreshadowing to the moment when Tom pulls the gun on Ginny and shoots at her on her way to the revival. Even though Ginny does not believe in predestination, it is clear that Robert Morgan is making a statement that some people or "savable" and some, like the Gibson boys and Tom, are not, no matter how hard Ginny tries to convert them.