"Fan Zone" is a side quest available in Dying Light.
Once you are in old town it will pop as troy will talk to you about some distress messages coming from fanzone. Once you enter the fanzone using the elevator on ground floor, you will find a no. of bodies lying on the floor. You have to first find a key card and the switch off the source message. As soon as you switch of the message,the man tells you that he is going to kill you and challenges you to escape. When you try to escape from the lift the lift will get stuck and and you have to escape from top. The room will be filled with gas so you will lose energy. The man will be equipted with a police rifle however he is easy to kill if you have gun. You can also find a german 9 mm pistol in the room. The mission ends with switching on the power.