Theory:Doctor Who television discontinuity and plot holes/The Invisible Enemy


 * Why when the infected crew members arrive on Titan don't they infect the base personnel instead of killing them?
 * * The crew member's infection is still in its early stages and is not yet contagious.
 * The cloning of the Doctor and Leela seems to have also cloned their clothes.
 * * (No doubt due to 51st century technological advances in regard to modesty.)
 * Several times during the episode, the signs for the "Isolation Ward" are spelled "Isolayshun."
 * * This is not an error, but an intentional aspect of the design to show a progression of the language at this point in history to phonetic spelling - i.e. spelling a word as it sounds. There are other such spellings, not only with the Isolation Ward but in the various other locations in which this story is set.
 * The interior of the Doctor's brain seems strangely lacking in fluid and other mucus that would drown the miniaturized Doctor & Leela. Also why is there a 'screen' with pictures of cogs and pillars floating across it?
 * * The Doctor's brain is that of a Time Lord, therefore there is no reason to believe its physiology should in any way be in keeping with the principles of human neurobiology.
 * * * Specific mention is also made that the miniaturized clones are not massive enough to break the fluid tension, implying that fluid is present but not discernible.
 * The interior of the Doctor's brain seems strangely lacking in fluid and other mucus that would drown the miniaturized Doctor & Leela. Also why is there a 'screen' with pictures of cogs and pillars floating across it?
 * * The Doctor's brain is that of a Time Lord, therefore there is no reason to believe its physiology should in any way be in keeping with the principles of human neurobiology.
 * * * Specific mention is also made that the miniaturized clones are not massive enough to break the fluid tension, implying that fluid is present but not discernible.


 * There are guns without triggers or holes in the barrel.
 * * They are energy weapons of the 51st century. They don't shoot bullets so they don't need a hole in the barrel.  They could be operated through hand pressure, or even through mental power of the user.


 * If K9 is Marius' 'best friend', as he says, why is he so content to part with the dog?
 * * Obviously, he has back-ups. The Doctor certainly does.


 * When the shuttle lands on Titan, the Captain flips down all the switches on the control. But he misses one.
 * * He seems to have purposely not flipped that one all the way down. Since we don't know what the controls are, we have no way of knowing what the switch's function is.
 * The surface of Titan – rocky with a clear view of Saturn – is inconsistent with what was known about Titan at the time the episode was made. It should be gaseous with an opaque orange sky.
 * This has been corrected on the DVD release, with other updated CGI effects.


 * Why doesn't Lowe simply shoot Leela the second her back is turned? Moreover, why does he take them to get medical help? It's made clear that the virus has everything it needs on Titan.
 * * He wants to spread the virus further, and the Bi-Al Foundation may contain technology to help.


 * The proportions of the shrinking Doctor and Leela clones is way off. At the point where they are two feet tall, they are still visible from above the waist (the foot tall door sill blocks everything below the waist). Their legs would have to be about 6” tall relatively to their 1-1/2’ bodies, torsos, and heads.


 * Why does Marius clone (and presumably re-infect) Lowe before injecting him? The Doctor needed to be cloned to go into his own mind, but Lowe doesn't. Perhaps clones are easier to shrink.


 * After the Doctor and Leela's clones fade, the camera pans to show Leela's knife. But since the knife was created in the cloning process, it should have faded out with Leela, the Doctor and their other personal items.