ATOMFALL best ending: How to Escape With Dr. Holder

What Makes Dr. Holder’s Ending the Good Ending?

Escaping Windscale is only half the problem: your choice can leave Oberon alive or condemn the quarantine zone. The ATOMFALL best ending is Dr. Holder’s poison route if your goal is to eliminate Oberon and escape without supporting Captain Sims’ plan to wipe out the zone. This ATOMFALL best ending guide covers the preparations, the toxin sequence, and the consequences that make even Holder’s outcome bittersweet.

Spoilers ahead for the six main ending routes described here. This guide focuses on the Windscale storyline covered by the supplied endings material.

Atomfall makes that decision deliberately uncomfortable. The official Atomfall Steam page describes a mystery driven by exploration, investigation, conversation, and consequential choices. Someone offering you a way out may also want research, military control, or something far stranger.

Holder’s route addresses the underlying threat rather than simply securing transportation. You help him prepare a toxin, administer it to Oberon, and escape through hidden tunnels. His closing dialogue says the whispering in his head is fading, suggesting the treatment has worked.

The strongest evidence comes from PC Gamer’s endings guide. It reports that Holder leaves an audio log if you destroy Oberon with explosives instead. That recording explains that the explosion only seals Oberon away, leaving it available for someone to discover later.

That distinction makes poisoning Oberon the strongest candidate for the ATOMFALL best ending. However, “good” is an interpretation of the consequences, not an officially confirmed canon ending. Holder’s escape still leaves you hiding from outsiders, and pursuing his lead can have deadly consequences for Dr. Garrow.

Unlock the Interchange and Reach Oberon

Before choosing an ending, you need access to Windscale and the Oberon dig site. PC Gamer identifies the following shared preparation sequence.

Image: Steam / Rebellion

Order	Required action	Location or equipment
1	Unlock all four Interchange entrances	Slatten Dale, Wyndham Village, Casterfell Woods, and Skethermoor
2	Activate the central processor	Use the battery found there
3	Power Data Stores Alpha, Bravo, Charlie, and Delta	Find four atomic batteries
4	Redirect power through the four junction boxes	Use a signal redirector in the central processor room
5	Pull the central processor lever	Central processor

These steps open the path to Oberon. They do not complete Holder’s personal lead or provide his toxin; those preparations are separate.

A good approach is to check the shared requirements before heading toward your final objective. Having the toxin ready will not substitute for powering the Interchange, and reaching the dig site will not automatically give you the item needed to poison Oberon.

Keep the battery requirements for different routes straight. The shared setup calls for a battery to activate the central processor and four atomic batteries for the data stores. Garrow and Joyce’s sample-extraction routes also use two atomic batteries to power the extraction drill. That drill requirement belongs to those sample routes, not Holder’s poisoning sequence.

For the ATOMFALL best ending, your priorities are the powered Interchange, access to Medical, and Holder’s prepared canister. The sample extractor, explosives, and fire safety system serve different objectives, so pay attention to which controls your chosen lead requires.

Find Dr. Holder and Prepare Poisoned Sample One

Holder is concealed beneath St. Katherine’s church. Reaching him requires a key found in the Medical section of the Interchange.

Image: Steam / Rebellion

His preparation sequence revolves around Sample One, which he turns into the toxin you need at Oberon. Do not confuse that canister with the meteorite sample extracted for Garrow or Joyce.

Preparation	What to do	Detail to check
Find the cellar key	Search the Interchange’s Medical section	The key opens the church basement
Meet Holder	Enter the basement of St. Katherine’s church	Agree to help him
Recover Sample One	Search the operating theater in Medical	The canister is beside a body
Return to Holder	Bring him Sample One and continue his lead	You need Poisoned Sample One for the final procedure

The practical sequence is to retrieve the key, meet Holder, agree to his request, then collect Sample One from the operating theater. Return the canister to him rather than taking the unprepared item straight to Oberon.

The Dr. Garrow complication

If you freed Dr. Garrow from Skethermoor Prison, PC Gamer’s walkthrough instructs you to tell Holder that she is in the Interchange. Holder then kills her in retaliation for abandoning him and the other scientists. Speak to him afterward to receive Poisoned Sample One.

That is a major consequence, not a harmless information exchange. The same guide explicitly warns that revealing Garrow’s location ends her escape option.

A good approach is to decide whether you intend to finish Garrow’s lead before sharing her whereabouts. Her route involves recovering research notes, using the GEN ERA command at Casterfell Dam Data Storage, and delivering an Oberon sample. Holder’s revenge prevents you from completing that escape with her.

The supplied walkthrough describes the Garrow confrontation conditionally, when she has been freed. It does not establish that freeing her is a universal prerequisite for Holder’s ending, so do not treat her rescue as an extra mandatory step.

Before leaving Holder’s preparation stage, check the item name: you need Poisoned Sample One. That is the canister used in the ATOMFALL best ending procedure. Mother Jago’s Growth Stimulant uses the same delivery system later, but produces a very different result.

Poison Oberon and Escape Through Medical

At the Oberon dig site, Holder’s route uses the fire safety system to deliver the toxin. You are administering a prepared substance through the system, rather than setting off the explosives around Oberon.

Image: Steam / Rebellion

Order	Action	Where to perform it
1	Open both fire safety system valves	Beside Oberon at the dig site
2	Insert Poisoned Sample One	Fire safety fluid input on the walkways outside the control room
3	Pull the fire safety system lever	Inside the control room
4	Return toward the Medical tunnels	Use the Slatten Dale Interchange entrance
5	Find Holder and leave with him	Follow the route into the Medical tunnels

Both valves are part of the documented sequence. After opening them, place the poisoned canister into the fluid input, then operate the corresponding lever inside the control room.

The distinction between the control room’s systems matters. The self-destruct lever belongs to the explosive route. The sample extractor lever serves the research-sample routes. Holder’s sequence specifically calls for the fire safety system lever after you insert his toxin.

A good approach is to verify the canister and control before committing. Holder and Mother Jago both use the fire safety apparatus, so the substance you insert determines whether you poison Oberon or feed it Growth Stimulant.

Finding Holder after the poisoning

The return journey is not simply a matter of retracing every entrance. PC Gamer reports that entrances have collapsed, requiring you to approach the Medical tunnels through the Slatten Dale Interchange entrance.

After crawling beneath the shutters, look for signs directing you left through the construction site. Follow that route to Holder in the tunnels and leave with him.

His final conversation explains why this escape is uneasy. The whispering is fading, and he expects the interference field to come down. However, he fears that outsiders will treat you both as specimens because of your blue eyes. He proposes remaining hidden and hopes that the visible effects will fade.

The ATOMFALL best ending therefore offers evidence that Oberon is dying and a route out of confinement. It does not promise public recognition, immediate safety, or a complete explanation of everything that happened.

How Holder’s Route Compares With the Other Endings

The reference material describes six main routes, each with a different cost. Comparing what happens to Oberon is more useful than judging an ending solely by whether someone gets you outside the quarantine zone.

Ending route	What happens to Oberon	What happens to you
Dr. Holder	The toxin appears to kill it	Escape through tunnels and remain hidden
Telephone voice	The dig site is destroyed; Holder’s alternate audio log says Oberon is only sealed away	Return to Bunker L8 and get sedated with gas
Captain Sims	You trigger the explosive sequence before Operation Atomfall proceeds	Evacuate by helicopter while the zone faces destruction
Dr. Garrow	Oberon remains intact	Deliver a sample and leave with Garrow
Joyce Tanner	Her route allows explosives or Holder’s poison after sample extraction	Hand over the sample and face interrogation by her associates
Mother Jago	Growth Stimulant strengthens Oberon	Jump into the fungal pit and receive an ambiguous ending

The telephone ending is straightforward once the Interchange is ready. You rearm four explosives, pull the self-destruct lever, and return to Bunker L8. The caller congratulates you, then releases gas. Their identity and your ultimate circumstances remain unresolved.

Captain Sims provides a much clearer evacuation, but the consequences are severe. After you complete his tasks and destroy the dig site, his escape instructions lead you to the helicopter at the Skethermoor Protocol Camp. Operation Atomfall then proceeds against the quarantine zone and its inhabitants.

Dr. Garrow offers escape in exchange for research material. Her ending leaves Oberon and the quarantine zone in place. You deliver the extracted sample to her office in Robotics, allowing her research to continue.

Joyce Tanner also wants a sample, but her escape ends with you being struck and taken away for interrogation. Importantly, her route can follow either the explosive sequence or Holder’s poisoning. Poisoning Oberon alone does not make the final scene Holder’s ending; the person you leave with matters.

Mother Jago asks you to strengthen Oberon with Growth Stimulant and then jump into a pit beneath the Castle Ruins. The ending describes becoming one with the soil and its voice, but the character’s physical fate remains ambiguous.

For an ATOMFALL best ending run focused on containing the threat, the decisive combination is Poisoned Sample One followed by escape with Holder. It addresses Oberon while avoiding the research handoffs and Sims’ destructive evacuation plan, though Garrow’s possible death remains a serious moral cost.

FAQ

What is the ATOMFALL best ending?

Dr. Holder’s poison-and-escape route is the strongest candidate if you want to eliminate Oberon and leave without supporting the destruction of the quarantine zone. PC Gamer’s guide interprets it as the good ending because explosives apparently seal Oberon away rather than truly killing it.

Does blowing up Oberon actually kill it?

The explosive ending presents Oberon and the Windscale plant as destroyed. However, PC Gamer reports that Holder’s alternate audio log says the blast merely seals Oberon away. His toxin route provides stronger evidence of its death through the fading whispers described in his final conversation.

Do you have to free Dr. Garrow for Holder’s ending?

The supplied walkthrough does not establish freeing Garrow as a universal requirement. It says that if you freed her, Holder’s sequence includes revealing her location, after which he kills her. You then speak to him to obtain Poisoned Sample One.

Can you poison Oberon and still escape with Joyce Tanner?

Yes. PC Gamer’s guide says Joyce’s route permits poisoning Oberon through Holder’s plan instead of using explosives. You still need to extract her sample, follow her escape instructions, and deliver it to her. That produces Joyce’s ending, including the interrogation setup.