Now head for the big tower in the cornfield and use the Thrustodyne Aeronautics Model 23 on the Navcard Machine untill the Element 115 rock is heated up. After a while, Richtofen will say he needs 115 from the zombies.
Now start to kill zombies under the Electricity Tower. Richtofen will say he needs a large group of zombies and you have to continue the slaughter. After some time (+/- 30 zombies), Richtofen will say that there is too much power, and you need to decrease the power by four.