The lights had been flickering on and off, as if someone were trying to balance the light switch(something that happened more often than you'd think, despite the fact that there was no actual light switch to speak of), for several minutes now. Having had what might qualify as a bad day, Imagination snapped at the mainframe in charge of this particular room.

"You have one job—one—and you are choosing to, rather than do it correctly, shatter the focus of everyone currently occupying this room. What in God's name is possessing you?"

The mainframe, being nonsentient, did not reply, and the lights simply continued their maddening flickering. Turning on her audio sensors once more, Imagination slid down her management rail, thinking to perhaps have a little 'chat' with the program in charge of the lights.

CRACKLE... CRACKLE...
Static flooded the radio channel. While usually filled with the various small demands of Her, all suddenly went eerily silent.
"Yes, hello?" responded, wondering if this was Her, ordering her to come to her chambers for whatever reason. However, there was no response whatsoever,which was odd in itself. Usually, if Imagination sent anything, prompted or not, onto the radio channel, She would reply with a sarcastic and most likely insulting remark.
But the lines were dead, and no remark came, insulting or otherwise.
More confused than anything, she slid down to Her chambers, curious to see what had happened, yet feeling uneasy the whole way, as if something was off, something she couldn't quite place.
When she reached the central chamber, she found it impossible to get in through the traditional entrance, it was too blocked. Which was saying something, as she was, in fact, on the ceiling. Luckily, having to come in through a back way on a few occasions, she was able to get in—obviously through said back way.

The chamber was littered with debris. Perhaps not littered—as littered implies that the debris was in small pieces. Chunks of the ceiling were scattered across the floor(making it very hard to navigate the disaster area), panels were thrown this way and that. Imagination was almost certain that she had seen a few parts of Her chassis in some places, and broken wires left Imagination at an impasse with the mess. Being unable to go much further to investigate, she left the central chamber, more confused than anything.
As she left the chamber, Imagination realized what had been off-nothing had been moving. The panels had been still. The conveyor belt had stopped, and the facility was silent.

Moving at high speed through the room next to the incinerator, she stopped in her tracks—something that proved to be a little awkward, causing something reminiscent of a screech.
Is that...?
A snarling, screeching sound came from the flaming room, filling every corner that wasn't protected by a wall. Having been in Her presence far too many times, the Imagination Sphere recognized that sound much too well—it was difficult to mistake the shrieks of the dying Anger Core.
But why is he in the incinerator? Is anyone else in there?
Moving a little closer, the Imagination Sphere thought that she could make out the shapes of two cores—one of them clearly the spastic Anger Core, the other being eerily silent as it melted. Shifting away from the heat rolling over her, she left the burning cores to their fate, more curious than ever now.
"Is anyone there? GLaDOS?"
It wasn't so much forbidden to speak Her name, more discouraged by the other cores—as you might discourage the use of profanity. As it would be grammatically incorrect to refer to Her in third person, the Imagination Sphere tentatively deigned to call her by her given name. No response came—not that she expected one, if parts of Her were in the incinerator, it was unlikely that She would be in any shape to answer calls.
Moving from the incinerator to the catwalks, to the offices, until finally she managed to catch a glimpse of the parking lot—and stopped again. Moving as close to the windows as she could, she peered through to focus on Her chassis, and was barely able to make out Her head hidden behind Her broken body on the ground.
How did she get out there? How did those scorch marks get there? How...

The questions currently threatening to burst out of her cerebral core would be answered in the following weeks, the answers being provided by security footage that had not been sucked through the portal, and se would understand the implications behind it, but for now, she forced herself to stop the questions and constant curiosity for a few moments to reflect.

This is a blessing, you know. Only a little while ago, you were wanting a better purpose than giving her creative ways to kill people. Now you have your chance. You can make something out of this. Forget the facility, if you can find a way to escape, you could make a difference.
Although she didn't know it, all hell was about to break loose. The facility would crumble. The reactor core would die, plunging the chamber into darkness. Most importantly, that lack of power would result in the deaths of thousands of test subjects, due to life support failure, and chaos would ensue.
And the Imagination Sphere would enjoy every moment of it.