If you were watching the season finale last night of NBC-TV's psychic detective series, 'Medium', you might have thought you were seeing a ghost in more ways than one. That's because at precisely 10:24 p.m., Barista Tyler appeared on the screen. "I nearly fell out of my chair," said one regular at Our Favorite Starbucks, "I had a sudden urge to run to the kitchen and get a cup of coffee." Tyler, whose debut lasted for nearly five seconds, played the role of a Federal Agent sitting at a conference room table. The series lead, Patricia Arquette, took one look in Tyler's direction and collapsed in a heap on the floor. Blood was pouring from her nose. She was later rushed to the hospital where inside sources say she will remain unconscious until next season. And boy is she in for a surprise when she wakes up. The series is moving to CBS this fall ...!