have you used the bathroom a lot in this class? Were there a series of students in you class using the bathroom before you left?

Do you get along with this teacher? Have you had other disciplinary problems?

Those questions need to be answered before you can be defended.

You are given time between classes, and lunch times to use the bathrooms. Teachers understand that emergencies happen and allow students to leave class sometimes, but it is to the teachers digression. If the teacher was in the middle of teaching something important, or if an examination was going on, or if another student was speaking, it makes sense for her to tell you to wait to use the bathroom. If you had a real emergency and you explained it to the teacher she would have probably let you go, but unless you have a bladder control problem you should have held it. It sounds to me like you went partially to annoy your teacher and be defiant, from the way you talk about it. You deserved to get reprimanded for being rude to your teacher, and they TALKED about expelling you they did not actually do it! You can not get expelled for defying a teacher unless you have a history of similar actions. So quit complaining, and apologize to your teacher

Well if you asked politely to go the teacher should have let you go unlees you do this often and were just trying to get out of class.

Ask them instead of expellling yo mabe give you a suspension or detention.

you did the right thing! now get out of government schools.