(adsbygoogle = window.adsbygoogle || []).push({}); First you have to open the door and get alot of zombies chasing you then you just go to the box and open it while you are being chased. After you will get flamethrower i have done this all the time with and without friends.

This doesnt work at all, ive tried it a few times but it hasnt worked once, so unless some videos are shown i dont believe it

Yeah, didn't work for me either.