Sometime later,
Sam is currently standing in the middle of an array. Both of you students are currently looking in his direction with a worried face.
This is the trial that Sam needed to go through to prove that he did not use any kind of illegal method to teach his students.
Previously, the principal gave him the option not to go through the trial as nobody had any kind of proof about him. But in the end, Sam goes through the trial.
First of all, if he did not want to go through the trial, then all those elders and teachers would become more suspicious. Even though he would not be able to prove anything, it would still slender his reputation.
He was not worried about his reputation, he did not want the students to get affected by this. Because of this, Sam goes through the trial to prove to everyone that he is not using any kind of illegal method.