When approaching Derek's unfinished house, a worried Alex tells Jackson, "You know there are bears out here." Alex had a run-in with a bear on Derek's property in 6x04.
The "Hobbit" patient calls April "a Dothraki Princess from the 'A Song Of Ice And Fire' series". This series was adapted to television by HBO, re-titled from the first book in the series, "Game Of Thrones"
When Alex is examining the "Hobbit" patient, Alex asks him to bend the knee. The "Hobbit" patient later refers to April as a "Dothraki Princess" as featured in the TV series Game of Thrones. The phrase "bend the knee" features heavily in Game of Thrones.
Each episode is named after a song. "What Is It About Men" is a song by Amy Winehouse.
The patient with the severed ear mentions they got a "T.A.R.D.I.S." which is from the sci-fi series "Doctor Who"