Theory:SJA television discontinuity and plot holes/From Raxacoricofallapatorius With Love


 * "The Slitheen" are referred to as a race whereas they are actually a family within the Raxacoricofallapatorian race.


 * Rahnius plans to steal K-9 Mark IV for its extensive knowledge of the past and future. This model has only been activated since early 2007 so will not have experienced all that much.
 * It is possible that this model has retained its memories of K-9 Mark III and possibly even those of Marks II and I before it. K-9 Mark I (at least) having been gifted to The Doctor (with Leela) by Professor Marius of "The Invisible Enemy" It is also possible that K9 has interfaced with Mr. Smith or the Doctor's TARDIS at some point. Another possibility is that Rahnius was mistaken in believing this model would contain such data. This K9 has been shown to have significant knowledge previously, including the TARDIS base code numerals (''DW: Journey's End).


 * Just before donning the red nose, K-9 is heard laughing. Is the tin dog capable of displaying such emotion?
 * Although never before heard laughing, K-9 has been heard sounding indignant, smug, angry, and in other emotional states in stories dating back to his debut in The Invisible Enemy. Sarah Jane or one of the kids might have also adjusted his programming.


 * How did K-9 get his red nose?
 * It was a Comic Relief Special, it was almost inevitable they'd work a red nose in somehow; ditto the funny hats given to the other characters. Exactly how it got there is a question left unanswered from an in-universe perspective. It is, however, very similar in appearance to the red deely-boppers that were previously materialised onto the humans in the room. It's not unreasonable to assume that the nose was also meant to be of similar origin.


 * The Slitheen in this episode has gas exchange problems but they managed to fix it in The Lost Boy.
 * The Slitheen in The Lost Boy are using a new type of "slimline" suit, which does a better job of dealing with the gas exchange. This Slitheen in no way appears to be wearing a slimline suit. There is no guarantee that the technology would be distributed throughout the family.


 * How could a Slitheen have trouble remembering the name of his planet?
 * He was pretending to be not a Slitheen.