Derek has thus undergone psychological (Flynn got away, and kidnapped his victim) as well as physical trauma, and this shows in his uncharacteristic brusqueness with Garcia. She handles this well, however, and Derek soon has his piercing focus back.
We learn that Billy has kidnapped the girl because he wants her to be his partner, that is, help him in his killing spree by having her open doors, literally, to his victims. He's attracted to her because she's intelligent and shows no fear, and these qualities help her divert some of Billy's plans.
J. J., who will (alas) be leaving the show soon, also has an excellent role, when she talks Billy into letting the girl go. J.J. has no experience as a hostage negotiator, so this is a major moment for her. She brings to the show a humanity, even a lightness of being, if that's possible, and Criminal Minds will be a little poorer without her.
Derek has the best line, telling Hotch that they (the team) were there for Hotch when he needed them, and now Derek would like Hotch and the team to do the same for him. Which they do, and all turns out as well as can be expected in these harrowing circumstances.
Never soft on on the eyes or the soul, Criminal Minds continues as one of the most intense, intelligent crime shows ever on television.
See also Criminal Minds 5.22 and the Dark Side of New New Media
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