I think Derek was so much more interesting this episode because of John's absence. (Where was the boy, I wonder?) The two actors are so similar in bearing that the writers seem to have trouble making them both compelling in the same space. Derek is something of a combination of John and Sarah's personalities — probably very similar to future!John — so he occasionally becomes redundant. I do enjoy BAG's performances when he's allowed to be more independent from the group, and he was very good in 'Goodbye to All That' (the military academy episode), so I guess he's just too hampered when both John and Sarah are around.

Also, hooray for Carlos Jacott! He really needs to stop pointing guns at Summer. It just keeps getting him killed.