To earn this achievement, you need to get killed by a Shooter.
Now the first place you can earn this is Contract 17: Mafia Manslaughter. You will notice there is a slaughter area in the top left of the restaurant full of pig carcasses, and there will be an enemy in grey up in this room. You can tell him apart because he is holding a gun in his hand.
Simply run into his field of vision and he will shoot you and you'll get your achievement. Be warned though, if he shoots you you'll (obviously) fail the contract and have to start over, so better to get this out of the way right at the start of the contract. Odds are you'll get this trying to complete the level naturally though.