Our local school district is re-doing its officer security program now with children like the one in OP.
The teacher will call in an AP and another admin person along with the campus resource officer.
The front office will use the office cell phone jammer until the child is secured.
One of the admin personnel will vid the entire sequence of events.
All children will be escorted from the classroom as the resource officer secures the door so that the offending child cannot leave.
When all children are safely away (probably the library), the officer will order the child to stand up, turn around, and put the arms behind the back. If the child refuses, the officer will wait for two more officers before securing the child.
The officer will secure and escort the child to the principal's office, where officer, principal, and child will wait for the jail personnel to arrive then take the child to custody.
When the child is taken away, the cell phone jammer will be turned off.
The parents will then be called.