•In ITA (Infiltrating the Airship) select "Grapple gun" at the start of the level.
•Next choose "wait" and on the desk there's a book with a key on it, click the key, make sure to do this before the next options appear .
•Then click "vent" and after that "leap".
This will unlock a guy in a holding cell.
•Select "Paperizor" and when you get through to the other side of the door a guy will fall from a vent on the right hand side, click on the usb on the broken vent.
•Click on "shrink n grow" then "armor".
•Lastly, when you get to the Disc options there will now be a USB stick at the bottom, click on it to reveal the code "1214".
•Go back to the start of the level and click "Earpiece".
•Click "Vacuum", once Henry is down the ladder click on the phone in the background.
•enter the code "1214" and a door will be unlocked.
•Finally, use the map and go to "Quarters Hallway".
•You don't have to do anything a cut scene will play on its own and you will get the achievement.