Theory:Doctor Who television discontinuity and plot holes/Rosa


 * The Doctor's TARDIS has a perception filter that means people "walk right past it" as the Ninth Doctor once said and many do. Yet, Krasko breaks through the filter despite not even knowing the TARDIS was in the area, thereby was not looking for it (a key component to breaking the filter's hold on passerbys) so: How did he notice the TARDIS?
 * Krasko's case, as stated by the Dcotor, had a perception filter. It is probable that Krasko is able to view objects through the filter somehow. Furthermore, he knew what TARDISes were, meanign he would most likely be aware of the filter, because of his case.


 * In (TVOxygen, set in the 24th Century, Dah-renn was confuse as to why a black person would be on the receiving end of racism. Here, Krasko, from the 79th Century, derogatorily calls Ryan “your kind”.
 * Racism could've come back, they could be from different places with different attitudes to race, many explanations.
 * Agreed - just because it's supposedly stopped in one part of the universe doesn't mean everywhere stops being racist. Plus, there's always the chance it comes back.