When Sawyer is taken back to his cage after the operation in several shots his heart rate monitor is replaced with a watch.
Juliet gets Jack to help her operate on Colleen. During the procedure she doesn't seem composed, and explains to Jack that she "is not a surgeon". Later in the series she performs an appendectomy on Jack and tells him that she "did lots of them" when she was in residency.
Near the beginning of the episode, when Desmond offers to help fix Claire's roof, just before Desmond starts speaking, baby Aaron can be seen in the lower left corner of the frame, but is obviously a puppet.