The next day...
"Thank you both for volunteering again," The man who had conducted the experiments on them yesterday addressed, "We now need to monitor you for..."
Sparks flew out from the machine and another white light ungulfed the lab.
Jon regained consciousness, "Success!" he thought, "Looking down, he saw Sarah's boobs busting out of her sweater, which seemed more frumpy than her usual...well, he could fix that now that this was HIS body.
He could only laugh to himself as he saw the other figures in the room stir to attention. Sarah, now in his old body freaked out, but so did the man conducting the experiment and his nurse.
"I don't know how this happened," the nurse stated, "this is impossible. Nurse Thompson...I'm you! Jon? Sarah? Are you both alright?"