That comment, however unknowingly uttered by Beckett, makes up for her rather uncharacteristic dig at the beginning of the episode, wherein she implied that Castle's work was not as important as her CV surgeon boyfriend's work is.
Not true. Takes all kinds of jobs to make us a well rounded species. However, I do agree with Beckett that most doctors (and other health care professionals) would rather sleep with someone outside the profession! FINALLY! Someone's writers got that one right!
But it was a well written tale of misdirection. First it was nurse Greg. Then it was the mystery man who turned out to be with the AG's office. Then it was Nurse Greg again. Then it was the reformed Drug Lord. And then it turned out to be said Drug Lord's jumpy brother...
The Nurse Greg and his maybe not-so-guilty-girlfriend angle was touching if somewhat of a reach. And nice that their hopefully not last meal together was from "Burgeropolis"...because while it would have been in keeping with the general theme of the show's discourse, to have used "In 'N Out Burger" would have been sooooo inappropriate! ;o}