Board Thread:The Panopticon/@comment-28874584-20160711192556/@comment-1432718-20160716173211

The specific rule here is Tardis:Valid sources. If something happens or is said to have happened in a story allowed under the rule, then we allow it on in-universe articles. We don't try to explain situations that the stories don't tell us, because we don't allow speculation on the main namespace of the wiki, so for now we don't know how Katarina was brought to the BA. And she may have only appeared in two TV stories, but she also appeared in the short story Scribbles in Chalk, where she had an adventure with the First Doctor and Steven, but only the Doctor remembers the adventure afterwards.

We do have a place for discussion of plot holes and discontinuities if you're interested. It's located at Theory:Discontinuity index.