How to crack open all three safes in Modern Warfare II to unlock the 'Gentleman Thief' achievement.
This is a guide on unlocking the 'Gentleman Thief' Achievement in the Modern Warfare II Campaign. There are a total of 3 safes across the campaign with secret codes. Once you have opened all three you will be awarded an Achievement. The first Safe is found in the Mission 'El Sin Nombre' and the other two are in the Mission 'Alone'.
Mission - 'El Sin Nombre'
Code - 02 02 19
The first Safe you will come across can be found in the mission 'El Sin Nombre'. After Soap has been interrogated he is free to roam the Cartels mansion. Head up to the second floor of the building and you'll find several bedrooms, you may have to kill some guards. A Throwing Knife can be found in the Kitchen of the floor you start at. Use this to kill the guards and Diego if you come across him. In one of these bedrooms is a wardrobe that you can open that reveals the safe, the code is 02 02 19. It contains an armour satchel and a shotgun.
Mission - 'Alone'
Code - 10 10 80
Follow the mission until you reach the Coffee Shop. Ghost and Soap will share a joke about British people loving cups of tea, it's hilarious... Before dropping down to exit the Cafe, find the door that needs prying open, it is to the left as you enter the Shop. Inside you will find the second safe.
The code is actually hidden in the Calendar in the room. To speed things up for you it is 10 10 80. You will be able to retrieve a throwing knife and a suppressed .50 cal pistol from this safe. Handy for this mission!
NOTE: The 3rd Safe is found on the same Mission. Don't leave.
Mission - 'Alone'
Code - 37 60 80
The third Safe is found in the same mission as Safe number 2, 'Alone'. In fact it is almost immediately after the Coffee Shop in the Car Garage. Walk through the Garage and you'll see a small office. In the corner of this office is the third and final safe.
The code for this safe is 37 60 80. This is the final safe you need to open. There is a Crossbow inside. This will unlock the 'Gentleman Thief' Achievement.