It's called "folie à  deux," or "the madness of two." It's a psychological syndrome, in which one deranged person transmits a delusion to another, creating a shared psychosis that's stronger than one could've developed alone. The second person can help push the first over the edge, and that can result in a psychotic break.  [So, you really think Emma and Audrey could be suffering from this madness of two?]  Seeing the news and the videos they posted online, it suddenly all made sense. I believe they can't move past their trauma, so they just keep replaying it. They may not even be aware of what they're doing.