Summarize this article in one sentence.
If a student starts to get violently angry, your first priority is to keep the other students safe.    If there is bullying going on in your classroom, learn strategies to stop bullying. You might think about dismissing the class early if the situation escalates. Don’t engage with the student until he has calmed down. Remain calm yourself, and don’t take sides. It may be a natural move to put your hand on the student’s shoulder to try calming them down. But when someone is angry, it is sometimes unclear what they may do in response. Maintain your distance from the student. If the situation has escalated, ask another student to get help. Having another teacher or person of authority may help diffuse the situation and can give you support. If there is a troublesome incident, such as a violent or excessively angry student, you should keep a record of what happened. Immediately after the incident occurs, write down what happened. Include details about what happened, when it happened, the names of those involved, and so on. Give a copy of this account to your administration. Also keep a copy in case a parent wants to see it. If the incident was severe, you or your principal will likely need to contact the student’s parents. Tell them the facts about what happened. Don’t add in your opinions. Stick to the facts. Use the conflict as a teachable moment. This is also a good time to reassure your students that they are safe in your classroom.

Summary:
Keep the other students safe. Keep calm and neutral. Do not touch the student. Send a student for help. Document the incident. Contact the student’s parents. Talk with your students about the incident.