Continuity mistake: Izzy tells the male patient she is a good doctor even though she was a model. Her hair is parted to the left and in the next shot it is parted to the right.
Continuity mistake: Arizona is wearing fitting black slacks and black heels and has two legs (not a prosthetic on the left). (00:37:45)
Other mistake: The exact same shot of Derek's radio tuner is used twice-once when he calls Amelia and again when he gets in the car after helping at the accident. Both times, the clock says 7:45PM, but Alana (the AP class taking, cello playing student) says that she's supposed to be at school, implying it's sometime between 8AM-ish and 3PM-ish. Also, the sun sets around 7:30PM in Seattle on March 26, but it is obviously day time for the duration of this scene so there's no way it could be 7:45PM in either of the shots in which the clock is shown. (00:03:30 - 00:18:40)