For this achievement you should load the 31 "chapter" by which i mean the 31 dot under the loading option.
OR "Load chapter 32 and walk left to the sub, avoiding having to escape the thing again."
Credit to: Funky Monkee
Then after you escaped from the
you will have to go through the ceiling with your submarine.
After you reach the surface go to the left until you reach a wall and jump against the ladder twice with your submarine to lower it, so you can reach it.
Get out, climb up and unplug the machine to get the achievement.