A more text based guide for those that prefer.
- Follow the mission story "certainty principle".
Once you gain access to the facility, you will get a tour and ultimately end up in Royce's office.
- She will explain the facility AI and say you can have a demo, and to come get her once you are ready. Wait for her to leave and CREATE MANUAL SAVE HERE! as you may mistime it.
- Basically at this point, you need to fire the staff in order and get the timing correct so that the outcome is Royce alone in the core and the safety mechanism is disabled.
- Fire Alicia Reynolds (top right) as quick as you can. This will cause her to go directly to the core to disable the mechanism.
- Fire Jeremy Bolt. (Bottom left) as soon as the option returns. He has some non skippable dialog. If you don't do this this quick enough. He will turn Alicia away and you need to restart. He will go and find Royce's guard to talk to.
- Now, keep an eye on the bottom right camera showing the core. You should see Alicia come in and interact with a switch at the right gangway. Fire Sharon Reed as Alicia interacts with this switch.
-Sharon Reed will activate the core before she leaves (10 seconds later). Alicia will walk out.
If this all timed correctly, Royce should have been alone in the core and the room will end up on fire for the achievement.