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: The scene where the bomb explodes shows the bomb squad captain walking toward the end of a hallway. Just as the bomb explodes you can see he is about 5-6 feet away from the end of the hallway where another bomb squad tech is waiting. After the explosion the scene cuts to Meredith flying backwards then to a shot of windows being blown out then back to a rear shot of Meredith hitting the floor. Notice here that a second floor is not visible at the end of the hallway. The scene finishes with a final aftermath shot of the hallway as the debris settles. Here we see an entirely different hallway with a visible second floor and the end of the hallway extended by about 10 feet.
Factual error: Derek tells Meredith to do an MRI on the lady that has a fork stuck in her neck. But an MRI-machine is actually a huge magnet; that's why there's absolutely no metal allowed inside of it. Doing an MRI on someone with a fork stuck in her neck is extremely dangerous.