A plant that drops that fast.......consider some sort of root disease such pythium or something along that line. The plant to does NOT look overnuted......just sick and sounding more and more like she's caught a root disease.

If you think she still might have a chance flush her with some ph correct water with H202 at 2 teaspoons a gallon (store bought 3% H202...OR..2m/gallon for 35%) and then place her in half nute strength ph correct solution with good aeration.

Get her away from any other plants and clean your hands thoroughly after working with her.

And pray. Good luck. I lost a beautiful power plant to the exact same type issue.