Go in as a demoman and setup sticky bombs at the entrance. Call in a heavy, backed up 의해 a scout and soldier, and wait on different sides of the area. PM the sniper to take out the teacher, while 당신 and other units go in to flank the teacher and capture the control point.
The enemy team will probably send out people, so it's a good idea to have a couple engineers setup some sentry 총 while you're at it. Another good thing would be to always have a medic nearby.