This unlocks as part of normal story progression. Towards the end of chapter 3, 2B and 9S confront a boss. They must survive the boss encounter and then escape the area where the encounter occurred. The achievement unlocks as soon as they reach safety.
The following
spoiler marked section is a short guide to the story related events that must be completed in order to unlock the achievement.
*** Spoiler - click to reveal ***The achievement unlocks during the Chapter 3 main story quest, Machine Surge. The quest is to eliminate the machines in the desert and report back to the Resistance Camp. Upon receiving the quest, follow the quest marker to the desert zone and speak with the resistance member with the unfortunate name of Jackass. She will use explosives to open up a passage to the desert.
Take this passage. There are enemies in the desert some in areas marked with red circles on the map. Destroy the enemies in the red circles. You may destroy other enemies as well. The main issue is to identify the small enemy that runs away speaking halfway intelligibly. This enemy goes to the desert housing district. Continue to follow it until you reach the bottom of a pit full of machines that appear to be acting human roles.
Attack them. This will cause the boss, Adam to appear. Try to kill him. You cannot but you will almost succeed. Upon surviving the encounter, the surroundings collapse forcing you to flee. A short cut scene indicates your objective--a small hole at the top of the pit.
Jump from collapsing walkway to collapsing walkway to get to that hole. It is the entrance to a passage that leads to the desert zone. The achievement unlocks as soon as you reach the hole. Note that neither the Machine Surge quest nor chapter 3 are complete at the point when the achievement unlocks.