Savannah Guthrie says she knew her mom, Nancy , hadn't just wandered off when she surveyed the scene at her home ... and she focused on one eerie clue in particular -- the doors were left propped open. In an interview with her "Today" co-anchor, Hoda Kotb , Savannah revealed her first thoughts when hearing about her mom's disappearance. She said, "We thought she must have had some kind of medical episode in the night and that somehow the paramedics had come, because the back doors were propped