When Strange is reading Through the Looking Glass and is coming up with a plan to create someone's backstory or persona it's a clear reference to a Batman villain, "The Mad Hatter" Dr Jervis Tetch who must be one of Strange's patients. See more
[Theo Galavan claws at the wall talking to himself
Rally to me. Rally to me. St. Dumas will deliver us. Dumas will deliver us. Rally. Heathens. And Dumas will protect us. Heathens, idolaters, Spawn of Satan, prepare to die! No. No. No, don't. Please. Sister? Speak to me, please. Please speak to me. Who are you? Huh? Who are you?
[as Ms. Peabody and Hugo Strange watch from behind the glass
Has there been any improvement since he woke up yesterday?
No. But he's wonderful, isn't he?