Theory:Doctor Who television discontinuity and plot holes/The Ribos Operation


 * How can the coordinates of the segment change while the TARDIS is in the vortex (i.e. outside space and time)?
 * Well, it is the Key to Time after all. In any case, if the reading was being taken outside of time all-together, then it would have to read the segment as being at an infinite number of points in time and space throughout its entire existence. To compensate for this, the locator is programmed to lock-on to a given segment relative to a specific timeframe. Once it has done so it will then proceed to track it within that timeframe, so any movements it makes would register even while the TARDIS is in flight.


 * Why do the trained soldiers stop when the Doctor tells them rather than obey the Graff's orders? ::Possibly due to a mild, mass-effect form of the vocal hypnotic / persuasive ability that Time Lords are known to use on occasion.


 * How can the Doctor walk out of the catacombs after they have been sealed?
 * There is mention of alternate routes out of the catacombs, such as the tunnel the Shrivenzale use for hunting.


 * Exactly how Romana not only ended up in the TARDIS but inserted the tracer receptacle into the control console so quickly is not explained.
 * Both of these events are attributed to the White Guardian's doing.