Load up any map With a friend, and with an easy access to guns at the start, i reccomend gunstore. Go downstairs into the gunstore, and behind the counter is a safe. You do not need the combination, as you can take the items inside without opening the safe. Let your friend get hit by a zombie a couple of times, until his screen starts flashing red. This means he has been infected. After a while, the virus will kill him, and he will be reanimated as a zombie. Now all you gotta do is shoot him. Boom, 'chieve get