This achievement is
story related and is unlocked just before you complete the Red Tape of Command mission when you pick up Olivia's journal.
CAUTION: If you want to get all endings in one playthrough, each with an associated achievement, make a hard save at the start of the Red Tape mission
BEFORE you pick up the journal and unlock this achievement. Do not overwrite this save.
Note: If you are going for the best ending in the full game, you will want to complete the game having unlocked the
Family Reunion DLC ending. The game's ending is heavily influenced by how you concluded the DLC. The
Postman DLC ending is one of the bad DLC endings, perhaps the worst. Accordingly, my recommendation is to do it first. The Postman DLC ending requires a specific action
BEFORE picking up the journal:
Once you comply with the precondition, you will be on the path to the Postman DLC ending and its associated achievement:
Whether or not you triggered the precondition for the Postman ending,
The Red Tape of Command mission is straightforward and can be completed simply by following the objective marker. Nevertheless, it can be made much easier if you enlist
PAM, the robot, whom you encounter as soon as you enter the facility. When you leave your ship to go to the Synthesis and Manufactory Center (SMC), include Parvati & SAM in your party. Parvati, with her engineering ability, will ensure you can enlist PAM.
Once inside the SMC, talk to the auto-mechanical in front of you, PAM. You get the optional journal entry,
Enlist PAM’s Help. The easiest way to do this is to have SAM charge her up. This is why we brought him. Otherwise, we would have had to seek out a PAM Unit Energy Cell elsewhere in the facility. After SAM charges PAM's energy up to 100%, use Persuade (or Lie or Intimidate) to complete this optional sub-task.
Go to Olivia’s Office on Floor 4/5 of the SMC map—you can follow PAM almost all of the way. She will lead you through the convoluted route in the facility to the final elevator. PAM also assists greatly in eliminating hostiles. Her combat capabilities are similar to those of your companion, SAM. Although PAM makes the mission easier, you do not need her. You can follow the objective marker and eliminate the hostiles yourself.
If you chose to follow her, PAM docks right before you get to the quest marker.
Pick up the journal off Olivia’s Desk. Doing so, pops the achievement:
The facility goes into lockdown. So, although you've gotten the achievement, you'll have to extricate yourself from the SMC. Hack the terminal next to where the journal was and cancel the lockdown. SAM in the party improves your hacking skills. Exit the door to the right of the desk. (If you can’t hack, you can crouch through a vent to exit the office.)
For a shortcut out of the SMC, take a right and go down the elevator. Unbar the door, exit the facility, and fast travel to your ship. You may have to kill some hostiles before you can fast travel.