What is Mark Kinney's role in the kidnapping in the book Killing Mr Griffin?

In "Killing Mr. Griffin" by Lois Duncan, Mark Kinney plays a central role in the kidnapping of their strict English teacher, Mr. Griffin. He orchestrates the plan to abduct him, motivated by a desire for revenge after feeling humiliated in class. Mark's character drives the plot forward, as his actions lead to unintended and tragic consequences for everyone involved. Ultimately, his decisions highlight themes of peer pressure and the impact of choices.