I felt every minute of the classroom scenes you described; I knew from the first exchange it was middle school. Great appreciation and respect for your ability to think about the child and not the fact that you were being disrespected. You didn't just let it go but neither did you jump all over an already agitated child. Instincts like that come from knowing the territory. In-school suspension is a valuable resource for the school and the child. What happens in there may not show its results for a decade, but I bet they remember it and remember you.