Confusion

Why do so many commentators state that someone suddenly disappeared? Can a person slowly disappear?

The cable T. V. people told me that I had to leave my phone open for a scheduled visit so that the cable guy could verify that someone was home before he came over. Wouldn't a busy line imply that someone is home?

A co-worker who was scheduled for minor surgery told me that the thing she hated most was that she couldn't drink any water immediatley before the surgery so she couldn't brush her teeth. What?