Oh how we laughed and laughed
Except I wasn't laughing
Under the circumstances I've been shockingly nice

Chell had repeatedly, without words, tried to explain to the AI that she wasn't there to kill her, but GLaDOS didn't seem to notice. Or care. The machine seemed rather preoccupied with something Chell couldn't quite put her finger on. Though it seemed it had something to do with her, she wasn't sure what.

GLaDOS pivoted back to face the former test subject and rolled her large yellow optic in a form of annoyance. "Well if you aren't here to kill me, which wasn't funny, by the way, why did you even come back? I would expect that even you aren't too idiotic to know what to do with your freedom."

Chell almost had to think about that for a moment. She couldn't have come back just for GLaDOS, could she? No, of course not. That would be ridiculous. That being the case, why had she come back? She paused to consider that, and suddenly it came to her. Now, how to actually tell the AI...

It appeared as though a game of Charades was in order.

Chell pointed to herself once.

"You..." GLaDOS repeated slowly. "Oh! Oh! Is the word 'annoying'?"

Chell rolled her eyes, shook her head, and moved on. She pointed to the machine.

"Me? What does this have to do with me?" she asked.

Chell tried to think for a moment. She continued blankly pointing to GLaDOS until she thought of something. After a minute of such idiot pointing, she looped her arms around her head in the shape of the letter 'C'.

"C... C... Companion Cube? I gave you back that incompetent piece of scrap metal, why did you need to come back?"

Chell shook her head quickly.

"Oh, oh! Cake! You want cake!"

If Chell was able to speak only for the next ten seconds, she'd use that time to tell GLaDOS to shut up. But, since that was only a fantasy, she shook her head again. She made another 'C.' This time, however, she pointed her arms above her head to form an 'A.'

"C... A..." the AI gave a synthetic gasp. "It is cake!"

Chell turned away from GLaDOS and stared at the ceiling, letting out and audible groan.

"Well, there's no need to get testy!" she retorted, "although I must say I think that's the most noise you've ever made."

Chell rolled her eyes and sighed to calm herself and then turned back. Instead of trying something she knew her arms were incapable of doing, she raised her arms into a 'V' this time.

"C... A... V... searching files..." her optic rolled backwards for a moment, as if all these files were inside of her. Which, in a sense, they were. She looked back to Chell, almost showing human confusion. "The only thing I could find under 'CAV' was 'Cave Johnson.' Is that...?"

Chell nodded quickly, and for a minute, she almost smiled.

"What do you need to know about Mr. Johnson?" She paused as if she had some horrible taste on her tongue. "Oh, sorry, I guess that name stuck after I deleted Caroline-"

Chell nearly jumped into the air on her Long Fall Boots. She wanted to scream 'THAT'S IT' but instead she just nodded repeatedly.

"Wait... you came back to learn about her?" the disgust in the AI's tone was blatant. "Why do you care?"

Chell pointed to herself again, and then made a motion with her arms like she was carrying an infant.
Then she pointed to GLaDOS once and made the CAV motions again.

GLaDOS stared blankly at her. "You... what? Is that supposed to make sense?"

Chell sighed and made the infant motions again. She then lretended to care for this imaginary baby. Then she pointed to herself.

"You have a baby?" GLaDOS guessed with bewilderment. "I didn't think there was a man on earth who'd want to do that to you."

Chell put her hands on her hips again, shaking her head once to show her resentment of that comment. She pointed to herself again, and with one hand still holding the invisible baby, she used the other to point to herself and then to the baby.

"Wait... so you are the baby?" GLaDOS asked slowly.

Chell nodded quickly, having to keep from jumping again. Then she pointed to GLaDOS.

"Me? No, wait, Caroline?" she asked.

Chell nodded. She pointed to the AI again, then held the imaginary infant.

"So I'm a baby too?"

The former test subject rolled her eyes and sighed.

"Well excuse me for not being able to understand you. It's not my fault you're mute." GLaDOS's optic rolled visibly.

Chell made the motions again. She hoped that this time it might make more sense, but was unlucky. In that, she was so annoyed she almost regretted coming back to Aperture.

"Oh, I give up with this idiotic game. Get in the elevator and go up two floors. You'll find a pen and paper. Then you can write whatever it is down."

Chell nodded and stepped back in. Everything would have been fine if the elevator wasn't clear. She went up more than two floors, and not only did the elevator keep going, but no paper was visible. Her face paled when a horrifying thought dawned on her. GLaDOS was trying to get rid of her.

The former test subject immediately banged on the clear door in an attempt to communicate 'Let me out!', but did not prevail. So Chell used what Aperture has taught her the most about: force. She elbowed the glass about five times when the glass finally weakened and cracked. The hole she'd made wasn't large, but with precision and the army of turrets on the floor she'd gotten to, she'd be safe. She rapidly waved her arms to a few of the devices still humming 'Cara Mia' to themselves. Their motion detectors caught sight of her and a plethora of bullets shot out. The glass shattered into shards instantly and Chell didn't hesitate a moment before jumping out.

Being on the turrets' floor put her at a disadvantage, but again, with precision, she could get out. She watched for a moment as the remains of the elevator sailed upwards.

She looked down at the tube it had come from, then back up at the transport. Then the former test subject had an idea. It was crazy, but it could work. She took a last look upwards, and then lept through the tube, saying a silent prayer to her Long Fall Boots.

Her prayer was answered when the fall didn't kill her. She stepped out of the tube and walked slowly until she was almost directly below GLaDOS.

"You," she mumbled. Chell didn't realuze she'd just spoken, as she was used to hearing a voice in her head.

The machinery spun around and looked down. When she saw Chell, her surprise wasn't at her presence so much as the sudden use of her vocal chords.

"Is there someone else here? I swear I heard someone speak."

"You tried to get rid of me!" Chell's voice was louder this time, and when it echoed through the lab, she realized what she'd done and clapped her hands over her mouth.

"Of course I did." GLaDOS replied calmly. "I told you to leave before and- wait. You can talk?"

Chell thought for a while before nodding confidently.