When you first arrive at the Interchange in Atomfall, you’ll likely run into the locked Site Office, with the Site Office Key nowhere in sight. The ‘Strange Noises From Below’ note that you can collect here, however, explains that the boss took the key to the construction site via the Robotics lab.
To access Robotics and ultimately retrieve the Site Office Key, you’ll need to have done a couple of things around the Interchange first. So without further ado, here’s what you need to do in the Interchange first, and ultimately where to find the Site Office Key in Atomfall.
Where to find the Site Office Key in Atomfall
The Site Office Key is found in the Robotics wing of the Interchange in Atomfall, though you’ll only be able to access this area after having restored power to the Central Processor and Data Store Delta (also in the Interchange) using an Atomic Battery. To then reach the Site Office Key, you’ll also need the Signal Redirector, which we explain how to get in our guide on where to find the Signal Redirector.
Fortunately, the Atomic Battery for the Central Processor is found beside a corpse in the same room. As for getting Data Store Delta powered, you’ll need to find another Atomic Battery; here’s our guide on all Atomic Battery locations to help with that.
Once you finally power up Data Store Delta, which then opens up access to the Robotics area, you can go upstairs (from where you placed the Atomic Battery) and out into the middle of the Interchange. If you look to your right in this area (provided you have exited into the Interchange from Data Store Delta), you’ll see a door with ‘ROBOTICS’ above it.
Enter Robotics, and in here, you ultimately want to open up the big grey door to the Lower Level. To do this, you’ll need to use the Signal Redirector to reroute power junctions inside of the Power Control Beta and Robot Assembly rooms respectively, ultimately powering the door to the lower level.
When you do reach the Lower Level of Robotics, there are three buttons – on three consoles – that need pressing to open up the Weapons Testing area. Now, you don’t actually need to do this, but if you fancy completing Dr Garrow’s quest, it’s worth doing so. These consoles also open up some of the quarantine seals on the lower level, making the whole area easier to navigate.
To grab the Site Office Key, you want to go through the tunnel in this area (lower level of Robotics) that is labelled with ‘EXIT’ on the floor and ultimately leads you back out to the Interchange. This is the only way of leaving the area, so you won’t have too much trouble ultimately finding it.
After going through the door to the Interchange, you will now be in a ruined underground area that is directly below the site office, with some stairs and a ladder leading back up to it. Just up ahead, there’ll be a corpse who has the Site Office Key on their body. There will also be some Feral enemies to take care of first.
When the Site Office Key is in your possession, you can return back to the site office via the nearby ladder that is just beyond the Slatten Dale Interchange entrance and unlock it.
Inside, you’ll find a case containing the Explosive Lure Recipe and a Training Stimulant, as well as some crafting supplies, shotgun ammo, and SMG ammo.
For more on Atomfall, take a look at how to upgrade your weapons, how to solve the murder in the church, and all Skill Manual locations.