On your second visit to VersaLife, you're tasked with uploading a ROM module to a terminal and then destroying the facility's UC. There are commandos, security bots and a female scientist. None of these NPCs can be killed or even knocked out, until you destroy the UC and successfully exfiltrate. You could just speedrun this, but even on Normal you get gunned down easily, so there's a stealthy way.
After you've climbed those pipes right above the water in the beginning, you'll enter a bigger pipe with only one exit that leads to a vent. Continue into the vent and a few steps later you should see a ladder on your 12 o'clock and a keypad on your 3. It can be bypassed with Multitools or you can enter the code
. Go down the corridor which will open up before you as the doors open one after the other. At the end of the corridor there is a stairwell which can be taken either left or right, since it leads above you either way. There's a camera on the right, so if you're on a No Proof run, deal with it accordingly.
Once at the top of either of the stairs, crouch and go opposite the security door to that stand which has a terminal on it. You can either hack it or try the following credentials:
. Turn the camera off if it's still operational and then make sure the door that's controlled by the terminal is on its upper position so you can go under it. Do so and go back down.
You can bypass the lasers by looking to your right and using some Multitools on the box. The security bots aren't active as long as you don't trip the aforementioned lasers or trigger an alarm. Hug either wall and use those triangular structures to hide from the Commando to your 12. He's patrolling perpendicularly to the corridor you're on, so wait until he's past the opening in front of you, where the scientist is standing in front of a computer. She doesn't move nor turn around, so simply move while crouched right behind her, until you can access the computer she's in front of. Hack it and select both options, then turn around and either wait for the commando to pass you again or go towards the other end of the corridor, away from him.
Follow the corridor until you find a ladder going down, it will be on your right if you took the left side of the corridor and on your left if you chose the other side. The scientist can't spot you from her position, so casually go down the ladder and follow the catwalk to a room with four Aug Cannisters, which can be unlocked with the codes 01, 02, 03 or 04, simply pick one and try all the codes until they unlock. Take the only route that doesn't backtrack you and you will easily find yourself to the bottom of this big shaft-like area, where you can easily find the UC's keypad, on the opposite side of where the scientist is. The code is 525.
As the destruction unfolds, jump in either of the four holes that open in front of you, but try to quickly get out of the pipes that correspond to each of them, as they contain a toxic fluid. To the left you'll be able to see another, fifth pipe, which is your way out. The following section is one where you need to keep resurfacing in the easily spotted sections of the various pipes in order to not drown, but there's also a baby Karkian in one of the pipes, which is also not to be killed or knocked out, so if it blocks your way try to lure it out in the open area and then re-enter the pipe it was in.
That was it. Keep finding the small sections that allow you to breath and eventually you'll find yourself back to the Canals. The achievement pops then or when you speak to Tong.