Spoilers for portal 1. If you haven't played portal 1 already, stop reading this and go play it. Have you finished the game? Good. Your life has meaning. Also, I have a wild theory: the cake is true.
You know how GLaDOS says the whole "burning you alive" thing was a joke? I suspect she was telling the truth. That the testing chambers really were just tests, that there really was going to be a party (pictured here, missing only Chell) and that they did expect her to show up, and that GLaDOS did indeed actually make cake. I base this on the appearance of an actual, made cake, and the fact that at the end that robot goes "thank you for assuming the party escort submission position". So I suspect that that robot just knows to drag people from wherever they lay down like that to the party room and I suspect GLaDOS didn't make the connection between the fact that she murdered everyone else and the fact that Chell doesn't trust her, hence why GLaDOS is doing the experiments on the coop bots in 2 vis-à-vis trust.
Also note what GLaDOS said to the lab rat in the comic: "Do you think it's a coincidence that you were diagnosed with schizophrenia and now you think a homicidal computer is out to get you?" So you know how when you confront GLaDOS in person that "morality core" drops out/off of her? Between the installation and uninstallation of that red eyed thing, I suspect she worked perfectly, as evidenced by the fact that she literally could not fill the enrichment center with neurotoxin until it came out. Also remember: Rattman (the guy that wrote the graffiti about the cake being a lie in the first place) also idolized the cube. So clearly that source is unreliable about the divine nature of the cube, maybe he is also wrong about the evil nature of GLaDOS.