Step 1 - Turn on the power and wait until the door opens. Then turn the power off.

Step 2 - Get the EMP grenade. Which essentially means you need to spam the box.

Step 3 - Reach the Pylon in the corn field. Between Farm and Power there is a split in the corn field. You have to jump off the bus and travel through it until you reach a giant electrical tower/pylon.

Step 4 - Power the Pylon. You need to put turbines on the left and right side of the tower on the side closest to the fence. You need two turbines. Dr. Maxis will start talking and once he finishes, pick up the turbines again.

Step 5 - Kill the Electric Zombie under the Pylon. He spawns at random so if you see him in the middle of a round, it is best to leave one zombie alive (crawler) and try to lead him under the Pylon. Place the turbines in the same spot you did previously and then lead him over to them. You need to hit it with an EMP grenade.

Step 6 - Grab more turbines and get all four players into position.