The camera hanging on Lewis Carroll's mirror has a tag that reads: "Click me". In "Alice in Wonderland", Alice finds a bottle with a tag that reads: "Drink me".
As Artie is leaving for his date with Vanessa, Claudia jokingly calls out, "Don't be yourself." This is likely a joking reference to the advice which Artie gave Claudia before her first date with Todd (back in Season 2). She had followed his advice to, "Be yourself," and the date turned out terribly.
Niamh Wilson, who plays Alice, also portrayed that character in her film debut - Chasing Alice (2003). She also played a character named Alice in Rookie Blue (2010).
The Opening pass thru from the front of Warehouse 13 to the observation deck passes by thru the Windmill then a Ferris Wheel Destroyed by bombs during World War II. Prater Amusement park in Vienna, Austria was a small marvel in the second half of the 19th Century, but bombs took out parts of the park, especially the Ferris Wheel.
Niamh Wilson (Alice) and Melanie Scrofano (Kristen/Alice) appeared in Saw VI (2009), though Wilson is not credited in that film.