1. Get in a group for a dungeon
2. Before you fight the last boss (tank is running to strike it) close your laptop lid
3. Wait 15-20 seconds (depends on how long it takes for your party members to kill the boss and leave) with your lid still shut
4. Open your laptop lid and Close WoW
5. Login
6. The boss should be dead and there should be a roll window. If your the only one in the group then it worked!
This happened to me except that instead of closing my laptop lid the power ran out.
Results may vary.