Separation Anxiety played on a theme that has been explored in science fiction many times before, that of somebody being out of phase with everyone else, and therefore invisible to them. Star Trek and Stargate have both done it at some time. It is one of those ideas that can be reworked in different ways.

In this case, a bomb puts The Doctor in hospital and Wyn out of phase. He wakes feeling perfectly well because his body can repair itself, but with some bad memories of flying through a plate glass window and a mystery. Where is Wyn. I wanted to get across his grief at not being able to find her in a real way. And in fact a bomb is about as real a situation as it is possible to get. Except that it is a space port and not an airport, the possibility had become far too real in the year since I wrote the story. And the idea of victims visiting a morgue to find their friends and loved ones is not fictional at all. There have been disasters enough on Earth where such procedures have to be gone through. And the mistaken identity and the collection of mobile phones is not in any way far fetched.

The conversation with Rose and the OTHER Doctor at that point seemed appropriate. Wyn, after all, came to the Tenth Doctor’s side from them. They would need to know. The first part is meant to make things a little less tense. His conversation with Rose about The Ninth Doctor jogging on the moon gives The Doctor a little respite from his worries. And his alternate self gives him a bit of a morale boost by telling him not to give up hope. The scene serves a purpose other than just to pad out the word count.

Then it becomes science fiction with a vengeance. Because The Doctor finds out what has happened to Wyn and has to find a way to get her back. And his way, of course, breaks the rules he holds dear, those Laws of Time. His justification, that she wasn’t dead and he wasn’t bringing her back to life by going back in time and altering events is a bit of a fine point, but enough for him to get away with what he did. JUST.

And when everything is fine and sorted, something else happens. Something I had planned for a long time. Because in the Unfinished Business series which was running consecutively to these stories I had one called Millennium Man which sees Wyn and Rose having to wait it out on SangC’lune while both Doctors went through the Rite of Progression. The next story would run on the same weekend as the Unfinished Business one. The last part of this story leads into it, explaining for readers of the TEN stories WHY he has to go through this dangerous ordeal. The same explanation with minor differences appears in the first part of Millennium Man.

http://www.pearsecom.co.uk/doctorwho/73milenniumman.htm