Coming Home (a.k.a. I've Got You Under My Skin) - S2-E10
Continuity mistake: When Carlos is about to be vaccinated, him and Gabby sit in the waiting room. Throughout their conversation watch Gabby's arms. At one point she has them down beside her, then in the next she has them folded. In the following shot they are down again, and in the next one they are folded.
Answer: He was investigating the lead not the case.