This is the first part of the Death Factory Mission in Hitman: Absolution which is called Test Facility. In it you eliminate Dr. Green with a signature kill and disable the security system. This guide explains how to complete this mission on the hardest, purist, difficulty. It does not explain how to complete the different challenges in this area.
At the end of this guide is a YouTube video with a visual version of this guide.
Recover the Stolen Files
Make your way down the corridor and enter the door at the left hand side of the start to the corridor leading off to the right. Inside is a key card on the desk. Retrieve it. Go back out of the room and go back into the first corridor. At the end of that corridor is a locked door. Open the door with the key card and go around the counter and activate the fire alarm. Then take cover on the counter in the middle of the corridor which also has the fire alarm in it on the side not facing the door:
A guard will leave the door and go to fix the fire alarm. Go into the interrogation room immediately after he has walked past you and pick up the file on the desk to the left and leave the room again.
Access the Test Facility
Take cover on the same counter as before and wait for the other guard to have gone back into the interrogation room. Then go back into the room you got the key card from and open the door using the computer in the front right corner. Then make your way to down the other corridor and follow it until you get to the elevator. Take the elevator down. As soon as the elevator stops reload from checkpoint, which will cause Dr. Green to start over with his test.
Eliminate Dr. Green
As soon as you load get off the elevator and go to the left and towards the crate you could hide in. When you are next to it turn around, pull out your silenced Silverballers and shoot out the glass underneath Dr. Green (it will take three shots):
Disable Security System
Go up the ladder to the left and immediately take cover on the wooden boxes ahead:
When the scientist has left and the guard is leaning on the railings to the right sneak past him and through the doorway ahead. Follow the stairs down and take cover on the wall at the bottom of the stairs:
Sometimes a scientist and guard walks towards you and sometimes they walk away. Either way wait for them to either have turned their back on you or have walked past you, then go down the walkway ahead and into the first door on the right. Sabotage the electric box, then go through the window to the right of it. Take the disguise sitting on the shelves, then turn around and go to the desk with the computer on it. Disable the security system.
Go back out of the room and up the stairs you went down before. At the top wait for the guard to be leaning on the same railings as before, then sneak past him:
Go all the way back to the ladder down whilst keeping out of sight of any guards that are patrolling the area (I can’ give you a definite guide since the guards weren’t at the same part of their patrolling route at the same time every time I played this mission). At the bottom of the ladder go past the elevator and into the decontamination area. Once you go through the exit door it is the end of this part of the mission.