You will have to complete day 1 & 2 of the Firestarter job to play day 3 in either Crime.net or Crime.net Offline. This mission is a classic bank robbery but with less assets available. This achievement will be MUCH easier if you successfully stealth your way into the vault. First things first, you'll have to disable the power on the vault door from the room on the roof. You will probably want to disable the cameras too by taking out the guard in the security room. The bank manager and 3 guards will be on patrol. Try to get them singled out and dominate them but be careful they don't get spotted on camera (if you haven't disabled them yet). If you have the ECM override, you can use it to break into the room on the roof and into the security room to take out the guy monitoring the cameras. If you get the manager down, he will usually drop a keycard that can be used on one of those doors. Both can be drilled but of course that takes time and makes noise.
Whether you succeed in stealth-ing the mission or not, you'll need to set up the drill on the outer vault door, and then drill through the inner door. Once inside, instead of setting up the camera, immediately start working on the safety deposit boxes. If someone sets up the camera first, that's not a big deal, it's just a little in the way for some of the boxes. However, DO NOT START THE FIRE. The more people you have lock picking the safe deposit boxes, the faster this next part will go. Whether you have triggered an alarm or not will depend on how many of you are free to lockpick. Alternatively, if you have someone in your party with the saw, they can rip through the locks in no time at all. The saw will eat up lots of ammo though, so bring as much extra ammo as possible.
NOTE: The poster must be picked up by the host! The achievement will unlock for the entire party.