I didn't see where/when Mariah was kidnapped/locked up. She was about to take a little weekend trip or something though? Because clearly she had her travel cosmetics/toiletries bag and a change or two of clothes with her in that room?
Maybe that's why people are suspecting Nina and/or Mariah is actually in the Chancellor house? She is not seeming like a true prisoner under lock and key in a cell, but more like how Nina was back in the late 80s when she was ensconced away, lonely, pregnant with Chance, in a back bedroom of Katherine's. LOL