This is the fifteenth level in Co-op mode of Portal 2 and the eighth chamber in the course. The chamber requires precise timing combined with the Flinging technique and thinking with four portals and the Thermal Discouragement Beam. Falling to your death and the giant fan are the hazards in this level.
The objective in this level is to first get the Redirection Cube in order to get past the giant fan. Then the players must use all of the four portals to direct the Beam into the other receptacle that shutsdown the fan. When the two players get behind the fan and use the Circuit Breakers successfully, they are able to insert the CD into the CD player.
Put your portal on the lower surface on the pillar behind you (marked with the numbers 01).
Shoot your portal on the surface with the numbers 02 on the pillar behind you.
Jump through your portal and you should hit the button that activates a timer when the Redirection Cube is about to pass by.
Jump through your portal when you hear the first or second beep from the timer. Wait until you are close enough to the Redirection Cube and try to catch it in mid-air.
Place the portal from the pillar to the pillar facing the giant fan.
Put the portal from the floor on the pillar next to you and go through the portal. Aim the Thermal Discouragement Beam at the receptacle in the small room in front of the giant fan.
Wait for the fan blades to come to a halt and jump through your portal. Walk through the Material Emancipation Grill and place a portal on the right side of the desc facing the Beam receptacle. Then continue walking to the right and enter the room with windows.
Place a portal on the small wall on the right, next to the catwalk staircase, and aim the beam trough the portal. Place the other portal on the wall near the tube that was transporting the Redirection Cubes.
Shoot your portal on the wall where the Beam ends. If the Beam is aligned correctly, it will connect to the receptacle and stop the fan from spinning.
Fire your portals on the pillar facing the fan and on the floor near the transportation tubes. Jump through the portal and go to the room behind the Emancipation Grill. Stand in front of the Circuit Breaker.
Use the Circuit Breakers at the same time (use of the Timer ping is preferred). Proceed to the staircase and get the CD from one of the tables and place it in the CD player.
Confidence Building Complete all test chambers in the Mass and Velocity co-op course
Triple Crown Solve 3 co-op chambers in the Mass and Velocity course in under 60 seconds each