b997eee8_CCG___What_s_That_Inside_Joke___In_joke
[Card] Susan (1) - “British” “Schoolgirl” [Exp.] Key [Type] PQ [In-joke] 
The overuse of quotation marks in the subtitle plays on Susan’s portrayal in An Unearthly Child where she is really neither.
Unauthorized Dr. Who CCG - What's That Inside Joke?
In-joke