The phrase "to disrupt the class" means to cause disturbance or interruption during a lesson or classroom environment, making it difficult for others to learn or the teacher to instruct. Full definition
His days of disrupting the class and being sent to the principal's office, a fairly common occurrence in sixth grade, are over, he says. (edutopia.org)
What about the students who seem most distressed, but don't disrupt class in any way? (educationnext.org)
However, a school can punish you for disrupting class by speaking out of turn or for leaving without permission, even if you did so to make a political statement. (nyclu.org)