(from AIOHQ)
One really disturbing fact about this episode is reported in The Complete Guide to AIO. It says that the "first part was written to be put aside in case Hal Smith (Whit) died. But we liked the story so much, we decided to finish it." They were originally intending to use the story as Whit's death if needed. As the episode that it is, I love it. It perfectly shows the issues and has an important purpose. But if they decided to use part one as Whit's death I would have been shocked. Can you imagine how all the people who had been so attached to AIO would have felt to find out the Whit, the central character everyone wishes they could meet, basically killed himself in an invention? I think it would betray a lot of what we know about Whit. Thankfully the episode was used where it was and they did not have Whit die when Hal Smith passed away in 1994, only a little over a year after this episode was broadcast.
- J

This episode received a lot of negative mail when it originally aired. As it ends with Whit flat-lining at the hospital, a lot of people were left wondering for the next week whether he was alive. It also aired near Thanksgiving, so many families were traveling and missed part 2, making the wait even longer for distressed kids.
- Jonathan

The episode title "Mortal Coil" may refer to Hamlet's "To be or not to be" speech in which he says, "When we have shuffled off this mortal coil, must give us pause." The mortal coil is referring to life, and by "shuffling it off" refers to death, so it is applicable to this episode.
- Hilary