Dr. Lim discovers that Morgan has been struggling with rheumatoid arthritis in her hands, leading to a mistake in the OR. Lim pulls her from surgery, reminding her that they "don't play through injuries". If you'd like to dive deeper, I can provide: A breakdown of the dialogue from the breakup scene.
Although Shaun tries to reassure Carly that he and Lea are just friends, Carly realizes that Shaun is actually in love with Lea. [S3E15] Unsaid
Later on, in Cory's operation, Morgan messes up. Lim entrusts her to do a couple of sutures but her RA prevents her from doing so. www.screenspy.com in Cory's operation