1) Get into a police station (2nd floor) in the corner of one of the smaller rooms.
2) Stay there for a while
3) Try to run out of the building as fast as possible
4) When you get warped back you may keep falling through the wall and falling on the ground from the 2nd floor. To stop this, lie down prone.
5) Voilá - You are stuck in the locked room on the second floor.