Phoebe was out with Jordan for the night before Jordan's limbs started swelling up. She accompanied Jordan to the hospital as Jordan's parents were both out-of-town.
Phoebe finally admitted that Jordan had been lying about following around the band all the previous evening and they then admitted that they had instead been following their favorite comic book author Jeffrey Keener.
Although Phoebe first told the doctors that they had not been separated, she later had to admit that Jordan had left the room at some point and she couldn't account for Jordan's whereabouts.
Later, Phoebe realized that Jordan was lying about what had happened the previous night. The doctors realized that Jordan was unable to control her lying.