If Elizabeth's great secret was that she was keeping a madman in her basement, I think he's probably a dead madman now.
I was thinking the same thing. I also wondered why Vickie hadn't taken the chance to explore the basement freely while Mrs. Stoddard was gone.
Roger calls Carolyn kitten again after comparing her to her mother in earlier episodes.
Elizabeth makes Vickie promise to tell no one she was in the cellar apparently meaning that she does not want Roger or Carolyn to know. She must now believe that Vickie is trustworthy since she has dropped her quest into why she was hired and how.