The final fragment will be found on the floor where you found Atton. The second one will be found after talking to the HK bot about the Security officer's last words. The first one is on the holo-log terminal where you will later import the password. There are three seperate parts to the password you'll need to find.
Originally posted by ThatOneFunnnyman:On my current playthrough, I was stuck for a bit on this too. Finally, if those dont work, you should be able to destroy the terminal to unlock the door(This does not give as much XP though). If you are on an easier setting, you should be able to regulally get the code from the HK. This is if you are on the most difficult setting though. After you have recorded all the correct fragments, you should be able to go back to the terminal that unlocksthe door to the outside of the station.
Look for the computer terminal that is found in the first room after the coridor that leads to the main room from the kolto tanks (sorry if this bit is confusing). On my current playthrough, I was stuck for a bit on this too.