Adagio Dazzle locks herself in the bathroom, fills the tub to the brim, and gets into the tub. Sunset Shimmer has been away from Equestria for years, but didn't start thinking of it as home until she had friends. It's been centuries since Adagio and her sisters came to this world, they've had just each other.
UPDATE: MADE IT TO POPULAR STORIES!!
HAS NOTHING TO DO WITH THE PONY POV SERIES.
With help from Kendell2.