Playing Portal 2, I'm at the place where Wheatley and Chell disassembles GLaDOS. So it's pretty much after cutting of her neurotoxin generator and crippling her turret production.

When Chell eventually gets trapped by GLaDOS, an administrative voice(voice of a scientist?) tells that GLaDOS is 80% corrupted and her core must be replaced.

Well, I'm confused about this: how did GLaDOS got corrupted at that instant? I mean, she's corrupted the instant she killed those scientists at Portal 1 ain't she?

I haven't played Portal 1 but I'm well aware of its plot.

An explanation for this sudden spike in corruptness is much appreciated.Thanks in advance.

2 Answers 2


This is not an "instantaneous" thing.

GlaDOS is a sentient AI. She has the ability to reason, justify, is completely self aware (i.e., she knows she is an AI that runs the Aperture Science test facility). In sci-fi, this can get dangerous. Long and short, GlaDOS is a rampant, sentient AI.

"The experiment is nearing its conclusion. The Enrichment Center is required to remind you that you will be baked, and then there will be cake." - GlaDOS; Portal 1 - Test Chamber 18.

Doug Rattmann, one of the few survivors in the Portal series, points out that GlaDOS has become dangerous, doubting the effectiveness of the Morality Core that was installed. His fears are confirmed, when she attempts to murder everyone with Neurotoxin.

"You can always ignore your conscience" - Doug Rattmann

The events of Portal 1 lead to Chell destroying several of GlaDOS' cores, starting with her Morality Core.

In the events of Portal 2, Chell and Wheatley gang up on GlaDOS to run a fail-safe procedure in an attempt to remove GlaDOS, and take control of the facility. This voice isn't anything more than the facility PA system reporting the results of the test, which has more than likely not been run before now; hence why GlaDOS is still in charge of the facility.

This "Corruption" is likely a test to check the integrity of the AI, and its "morality". Since GlaDOS is responsible for mass murder, torture, imprisonment, etc., it is fair to say that she is pretty damn "Corrupt".

Though, following the events of Portal 2, it becomes apparent, since she decides to forgive, and even reward Chell by releasing her once GlaDOS retakes control of the facility, that she is not completely corrupt, and therefore she is able to redeem herself.

So, to recap, the test that reports an "80% corruption" is not an instantaneous "spike". She has, over time, built up a corrupt sense of morality, and this is the first time this test has even been carried out, since she had previously killed anyone that might have been capable.


In short - there is none.

There is actually no cannon explanation as to why she is corrupt at this moment. At no point in the story do we get told what made her corrupt, as (spoiler for end of story):

At the end the PotatOS get's put right back inside wheatly - despite her "corruptness".

The only possible assumption I could make is that by having her cores removed from Portal 1 "corrupted", thus why she was 80% corrupt.

If course you could also say it "detected" her evilness but then again (more spoilers):

Why did it not pick up on evil wheatly at the end, and why did it let GLaDOS be put back in.

Overall, this question is one of the more major plot holes in the story.

In response to the comment "Is it because GLaDOS tried to kill Chell" (Portal 2 spoilers):

Wheatly also tried to kill Chell multiple times yet you still had to manually corrupt him with cores before it would allow a core transfer

  • Is it because GLaDOS tried to kill Chell? I mean, this all corruptness is measured on how GLaDOS behave towards humans. So when GLaDOS tried to kill chell she became more "evil"? Does that make any sense? Commented Apr 1, 2018 at 14:44
  • Will edit my post to answer as it too contains spoilers. Commented Apr 1, 2018 at 14:45
  • 3
    Personally, I interpreted this comment to mean she was 80% corrupted in relation to what she expected. As in, all the shenanigans Wheatly and Chell had gotten up to, disabling her turrets and nerve gas, etc, had corrupted 80% of her systems. It's not about how "good" or "evil" GlaDOS is, it's about whether or not her systems are functioning "properly" (as GlaDOS defines "proper").
    – Steve-O
    Commented Apr 1, 2018 at 16:11

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