We Are Never Ever Getting Back Together - S10-E22
Other mistake: When Meredith is talking to Kenzie about the conjoined twins, she is wearing a lab coat that says Seattle Grace Mercy West. The hospital is named Grey Sloan Memorial at this point. (00:20:00 - 00:21:00)
Other mistake: When Derek has finished showing Callie and Arizona the picture of Cristina getting her nomination, he leaves to take the kids into what we are supposed to believe is daycare...however the sign on the door reveals it is a dispensary. (00:02:30)
