In Atomic Heart, players have the intriguing option to embrace either extreme: eradicating every character they encounter, or navigating the world as a committed pacifist.  Studies consistently show a preference for 'good' choices in video games, suggesting that most players won't opt for a complete massacre. However, for those who do, Atomic Heart ensures a functional path to the game's conclusion.

The pacifist route requires a similar narrative consideration.  To ensure a satisfying ending regardless of playstyle, Rebellion's Design Director, Ben Fisher, explains that the team implemented a 'narrative backdoor'. This mechanism ensures that every player, regardless of their choices, can experience a complete narrative arc. The chosen tool for this narrative safeguard is none other than one of Britain's most recognizable icons: the classic red telephone box.

The possibility of a complete massacre is actually one of the reasons behind this quintessentially British element's inclusion in Atomic Heart. Fisher clarifies that the decision was twofold:  solving the narrative challenge posed by mass murder, and drawing inspiration from a real-life experience of Jason Kingsley, one of Rebellion’s founders.  Fisher recounts Kingsley’s anecdote: "He was walking in the Lake District, went past a phone box and it rang. It's odd. Why is this phone box ringing in the middle of nowhere?" This unsettling experience, combined with the narrative design problem, led to the creation of an unkillable character within Atomic Heart.

"We wanted to use this thematic element because it was such an intriguing, and slightly unnerving, moment, so we married the two things together. If you *do* kill everyone, there's still a mysterious voice on the phone line that will, to some degree, guide you through the world. It might not be the best route, and it's certainly not the *only* route, but you can’t shoot the guy in the phone box, can you? It’s the failsafe for the mass murderers."

As players explore the world of Atomic Heart, these phone boxes will occasionally ring. Answering reveals a distorted voice that offers guidance, commentary on the player’s choices, or observations about key items.  This element injects an air of mystery and suspense into the gameplay. While perhaps not as startling as Kingsley's real-world encounter, it remains an unsettling and intriguing feature.  The voice’s identity, motives, and uncanny knowledge of the player’s actions remain shrouded in secrecy.

If a character within Atomic Heart is the source of this voice, and integral to the ending, players might theoretically be able to eliminate them. However, the game's design suggests this character may never be encountered directly, or their identity revealed at all. While improbable, given Atomic Heart’s emphasis on player agency, it’s conceivable that some players might entirely ignore the ringing phone boxes. For now, the true nature of this enigmatic voice remains a mystery, waiting to be unveiled upon the game's release.