You may get this sooner but for me. I unlocked this on the stage
Military Junkyard. You'll be at this stage when you unlock the achievement
Machines Can Expire Too (story related)
When you're at this stage;
Go Left
Go down x1-
You should now see a computer in the middle of this area. Just press
when prompted by the computer. It'll start a flash back scene where you control a human. After finishing the flash back scene. You will unlock
The Darelictachievement -
Relieve the First Flashback Sequence