Sarah, in a panic, pushed random button on the Chronivac hoping that she might get lucky and Katherine might come back out of her and be okay. Unfortunately, the button she hit just before pressing enter had set the machine to regress it's last target further.
Sarah gasped in shock as the nausea suddenly passed completely and she felt her womb shrink back to it's former size. She noticed one other thing: a damp sticky felling in her panties. Worried as she was about her sister, Sarah forgot about her for a moment in her haste to figure out why her groin was suddenly sticky.
She lifted her skirt and pulled out her panties to see that the inside of them was covered in a sticky white fluid that looked like it had leaked out of her vagina. What Sarah didn't know was that Katherine had been regressed back to before she was conceived. She had been separated into an unformalized egg still floating in Sarah's womb and a few ounces of cum which were now leaking from Sarah's vagina.