After Sister Jude Martin (Jessica Lange) gets a dose of her own medicine, she becomes a lot more relaxed, but that's probably a result of the shock treatment therapy that melts her brain. Sister Jude receives her own treatments first hand and it's only when she discovers the pain of these treatments first hand that she realises how cruel and malicious she has been for all of those years. It is this epiphany that shocks viewers the most, as she morphs into a deranged and lifeless patient, so when the dancing starts, it's particularly creepy. This particular episode channels a lot of Glee dance moves and cheeriness as a mass break out dance occurs amongst the patients. Considering the location in which it is set and the horrific events that led up to this moment, it does actually make the dancing a lot more unsettling than it appears to be. The dancing represents the freedom that the patients no longer have and because of the treatments which are dehumanising them, this dance routine is essentially a cry for help from their former selves. It's more eerie than cheery.