Continuity mistake: During the operation on the Asian girl from the market, a stitch breaks and Christina is covered with spurting blood, including all over her mask. When she turns to leave the OR, the all-over splatter on her mask has turned to dribble-like streaks instead.
Revealing mistake: When Derek Shepherd tells Meredith about his wife cheating you see Meredith Grey standing by her car and you can hear and see the rain all around the trailer, while Derek Shepherd is sitting on his porch under an overhang. Before Meredith sits down you can see rain hitting the hood of her car. When Meredith sits next to him she is completely dry. When she goes back to her car the camera does a close up and she is still completely dry even though her car is covered in rain drops and you can see the rain in the background. (00:37:10 - 00:39:40)
Continuity mistake: In the first overhead shot showing Izzy lying under the Christmas tree, you can see Meredith's hair to Izzy's left but then the the next shot is Meredith coming into the room and Izzy under the tree by herself. (00:41:05)
Continuity mistake: When Christina notices the bomb squad moving Meredith down the hallway with the gurney, she leaves the room and removes her scrub jacket and hands it to a nurse. When she is out in the hall and reaches them, she suddenly has the scrub jacket back on again. (00:18:50)
Continuity mistake: When Derek talks with Mr. Chue in the rain under their umbrellas, in one shot Mr. Chue takes a big puff on his cigar. But in the next shot his face is relaxed and it is clear he didn't inhale; and then he takes the same puff again instantly anyway. (00:19:20)
Continuity mistake: As Meredith tries to get in to see Christina, but Bailey walks over to stop her, Meredith is putting on a white surgical mask. In the frontal shot she ties the white straps of the mask into bows. But in the next shot from behind the straps hang loose and aren't in bows. (00:29:50)