I liked this episode for alot of reasons....but the main reason is that I love unhappy endings. Not every story could or should end in death, but I seem to like stories that are not tied up in such a nice bow. When I originally heard the title, I thought it would be like Invasion of the Body Snatchers. But I liked this story because it well could have happened. And who knows .....it might have.
CardsFan--I am currently listening to the episodes around this time period....I'll let you know if I come upon the episode in the preview.