Since we don't exactly know what happened to Caroline, it's a headcanon of mine that her body was put into a cryo-unit like Rattman in the comic (spoiler?) when her mind was put into GLaDOS and may have been killed when he saved Chell at the end. So I present to you, Feels!
I own nothing!
Down in one of the many lab rooms of Aperture Science Facility as Alfred and Matthew made their way through a quiet field of wheat, a lone body lay in a cryo-unit. His eyes were closed and his hair was slightly tousled as if he were just asleep and tossing in his dreamlike state.
He was blond and thin. If one were to look closely, they would notice he wore a starch-white lab coat with a tiny emblazoned Aperture Facilities over his left breast. And if one were to look closer, more carefully, they would notice the stitches that had been removed over his right breast could still be faintly made out. They read M. Williams.
His chest moved up and down very hesitantly. The cryo-unit was keeping him in a state of preservation, in a long sleep, with no wake-up date dialed in.
Arthur watched him from one of the cameras placed in the room.
Matthew's body was still here. Matthew's consciousness had just left.
Arthur watched the body in the cryo-unit for a long time.
His own body was gone, destroyed in the humans haste, but this body was still intact. His emotion-sensors were override with jealousy, rage, contempt. But behind those, he felt a tiny pinging that stood for sorrow, pain. And the last thing his emotion-sensors picked up on, as he opened the cryo-unit, dispelling the air and ultimately killing the human with no soul, no mind, no life, was mercy.