Where to find the church cellar key in Atomfall

If you're looking for the church cellar key in Atomfall, you're in for a lot more than you bargained. You were probably thinking this key was just tucked away in St. Katherine's church somewhere and that you could quickly grab it for some cheeky looting. Alas, it requires a fair bit of progress into the Interchange before you can grab the church cellar key.

For those who don't know what an Interchange is or who've only just arrived in Wyndham Village, you might want to check back here later once you've explored a bit more, since this key requires a bit of progress to get—though it's well worth it for the secret contained within. If you're still with me and ready to jump through a whole lot of hoops, here's how to get the church cellar key in Atomfall.

Atomfall Church cellar key location

You can find the church cellar key in the medical wing of the Interchange. Specifically, as soon as you enter the area, turn right, and then right again to find it on the floor at the end of a cramped lamplit corridor by an audio log.

If you haven't ventured into this sprawling bunker complex yet, you'll find yourself there soon enough, but you'll have to complete a fair few tasks to get to where this keycard is. To start, you'll need to enter the Interchange in northeast Slatten Dale—the concrete bunker you can see on the hill north of the Outlaw Camp.

Open the big door to the Interchange using the modified keycard and then head to the central processor where you can power up the facility using the atomic battery on the floor in that room. If you look around the central room, you'll see a sign above one of the doors listing "Medical" but you can't open the door.

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This is because the medical area is only accessible via the Interchange entrances in Casterfell Woods and Wyndham Village—just to the left as you enter the area, and just to the southeast of St. Katherine's church respectively. You'll also need a second Atomic Battery to power up the area, and plugging it in requires braving a room filled with blue spores. I suggest finding Mother Jago in the northeast of Casterfell Woods and undertaking her lead to acquire the Strange Tonic Recipe.

This consumable gives resistance to the spores so you won't die in Data Store Alpha while trying to insert the atomic battery. To power up the area:

1. Enter into the Interchange via the Wyndham Village entrance
2. Open the smaller door and then the big door using the modified keycard
3. Take the first left, avoiding the rat swarm, and crawl under the slightly raised door
4. Go through the door straight ahead and descend the stairs
5. Drink your Strange Tonic and brave the blue spores, descending until you find where you can insert the atomic battery

Now you've powered up Data Store Alpha, you can access the medical area. Head back under the raised door and sprint down the corridor—again, avoiding the rats—until you see the "Medical" sign pointing left. Unseal the door, follow the corridor, and turn right down the stairs to find the entrance to Medical. You did it!

This area is filled with tough thrall enemies, so be sneaky as you enter, turn right at the front desk, and then right again into the small lamplit cramped corridor described above. The church cellar key is just on the floor there. I bet you're wondering what the hell is so valuable that it requires so many elaborate steps to find.

It's not a treasure as such, but actually quite an important character, so go back and unlock the church basement and say hello. Among other things, this scientist gives you the Infection Resistance skill for free, which is a godsend for traversing areas filled with blue spores, and he also unlocks the Radiation Resistance and Healing Boost skills for you too.