Factual error: In the opening scenes, Arizona mistakenly says a child suffering from eminent liver failure is at risk for psoriasis, when the script called for the word cirrhosis. Psoriasis is a skin disease. Cirrhosis is the medical term for end stage liver disease.
Continuity mistake: Cristina walks in during the party with two containers of cupcakes, places them on the side table and walks out. When Alex opens the lid and starts picking at the cupcake toppings, in the shots facing him the top container lid is wide open, but in shots facing Meredith the lid is closed and the cupcakes are untouched.