GlaDOS was stumped. She couldn't figure out how to get Chell, her human test subject to cooperate. It had been three weeks since she had returned to Aperture Laboratories, and yet she wouldn't perform a single problem with this being that it was a part of the deal.
Chell had written down that she had wanted her voice back, but GlaDOS had refused. But Chell wouldn't leave, so GlaDOS decided to make a deal.
"I will have your damaged vocal cord repaired, but on one condition. I need a test subject, and you are unfortunately the only one left. Run tests for me, and you will be able to speak again."
Chell had simply nodded, and returned to her living quarters.
At first she performed admirably, but as time went on, her performance steadily began to decline. GlasDOS needed some way to motivate Chell. But how?