Warning! This article contains spoilers for Silo season 2.

Silo season 2 has introduced viewers to many intriguing story developments, with one revolving around a mysterious protocol called the Safeguard. The term first appears in the series when Lukas decodes a few lines from Salvador Quinn's letter. "They created the safeguard," says one line, hinting at how the founders planned to suppress chaos in the silos. However, like Lukas, viewers remain clueless about what the Safeguard means until the character sets out to look for answers.

Silo's main characters, like Bernard and Lukas, learn the truth about it in the Safeguard, Juliette is exposed to the term when Solo recalls everything he knows about it. Many aspects of the procedure remain shrouded even after Silo season 2, but the show drops enough clues to help viewers fill in the blanks.

The Safeguard Procedure Kills People In The Silo Unless Stopped

It Is An Extreme Protocol Designed To Terminate Silos

In Silo season 2's episode 9, Lukas finds the tunnels under Silo 18 after learning about them through Salvador Quinn's letter. When he approaches the tunnel's massive entrance, a voice dubbed "The Algorithm" in the subtitles warns him that if he tells anyone about what he is about to learn, the Safeguard will be implemented. This hints that the Safeguard is an extreme measure that could potentially destroy an entire silo.

...During the procedure, poison is released into a silo through a pipe connected to an outside source.

Before Juliette leaves Silo 17 in Silo season 2's finale, Solo suddenly re the Safeguard procedure after finding a written note about it in his home. He reveals that, during the procedure, poison is released into a silo through a pipe connected to an outside source. This confirms that the Safeguard has been designed to eradicate the people of an entire silo if they turn defiant and stop obeying the founders' rules. After learning about the procedure, Juliette rushes back to Silo 18, hoping it is not too late to save her people.

Who Controls The Safeguard Procedure

The Algorithm Determines A Silo's Fate

Silo season 2 establishes that the Algorithm observes patterns and conditions inside a silo before determining whether it deserves to sustain itself or be destroyed. Many details in the series hint that it is an advanced AI designed by the silos' founders to ensure their vision for the underground structures is met. However, some aspects of the Algorithm make it seem a little too human, making it hard not to wonder if real humans are behind it.

For instance, the Algorithm seemingly appoints Camille as Silo 18's new leader in season 2's ending moments, suggesting it has been keeping a close eye on Sims' wife's behavior and measuring her potential to become the silo's head. Bernard also mentions the founders created 51 silos, making it hard not to believe that one silo is being used by "bigger evil forces" to monitor and navigate all others through the Algorithm. This could mean that the Algorithm provides relevant data to the leaders in the additional silo before they call the shots on which silo deserves to live.

How The Safeguard Procedure In Silo Can Be Stopped

Solo Tells Juliette How She Can Save Her Silo

After telling Juliette about the Safeguard procedure, Solo recalls that it can be stopped by merely blocking the pipe that releases poison into the silo. Although he does not delve into the details of how the people in his silo blocked the pipe, Juliette will likely figure out a way to do the same if she finds the pipe in her silo. Throughout the series, she has shown her engineering prowess and found creative ways to solve her problems. For someone like her, sealing the opening of a pipe should not be a big deal.

Where Is The Safeguard Pipe & How Does It Work

Solo Confirms The Location Of The Pipe In Silo 17

Before Juliette leaves, Solo also reveals that the pipe is located on the 14th level in Silo 17. Since all silos seemingly have the same layout, the pipe in Silo 18 should also be on the same floor. Solo even attempts to show Juliette the pipe, but they feel the tremors from the explosion caused by the Mechanical in Silo 18 before he can take her to level 14. As a result, Solo encourages Juliette to return to Silo 18 before it is too late for her to save her people.

Did Jimmy's Parents Successfully Stop The Safeguard Procedure?

Solo Implies His Parents Found A Way To Save Silo 17's People

Solo says his mother worked at Silo 17's level 14 and did not return home on the day of the rebellion. This could mean she tried to block the pipe to save her people from the poisonous gas. He also adds that his father had found a way to make the outside world safe, and Silo 17's people also initially seemed fine when they stepped outside. However, moments after they left, a wave of dust came towards them and killed them all.

Warning! Spoilers ahead for Hugh Howey's Silo books.

In Hugh Howey's original Silo books, it is revealed that lethal nanobots are released inside silos to wipe out all citizens when a silo is deemed unfit for sustenance. The same nanobots, mixed with argon gas, are also in every silo's airlock chamber, ensuring that cleaners with faulty tapes die soon after getting exposed to them. The books also reveal that the nanobots can be re-programmed to heal humans instead of harming them. Solo's story in Silo season 2 suggests that his father might have found a way to re-program the nanobots, but the citizens who stepped out were exposed to "dust" containing bad ones, which killed them.