I'm a big fan of the show and liked the episode, as usual, for the characters, camaraderie, banter, humor, etc.
I'd like to take the opportunity here to list some quibbles, which apply to many other episodes as well:
¶ after discovering the first bunker with the dead woman in a wedding dress, it was a big guess for Kate to assume that the murderer was a serial killer who wouldn't stop killing till he found his perfect "wife."
¶ it seemed far-fetched to take the whole team down South to a Naval base there, where there is a missing female petty officer, largely because they found a Southern beetle in the first bunker. But again, I guess NCIS has time and money to burn.
¶ it seemed wasteful (to me) from a time and expense perspective for Kate to reconstruct the bunker at NCIS headquarters.
¶ although there were a few other clues mentioned, one of the main reasons for Gibbs' suspecting the cleric is that he might have worn silk "shawls", and a thread of silk was found in the first bunker. A "thin thread" for an assumption if there ever was one! When Gibbs and Kate approached the cleric the second time, it was foolish for him to shoot himself -- after all, what evidence could they have against him?
¶ Gibbs had no good reason to RUSH the expensive full throttle search for the missing woman at the end -- based on his far-fetched assumption that the cleric would turn off the oxygen again, or that he had time to turn it off.
¶ finally, I am glad that Gibbs (and the others) have mellowed some since the early seasons. I seem to find a lot of unnecessary, mean, nasty jibes thrown at each other in early seasons. For example, when Gibbs announces he is going to interview the missing woman's roommate, the female NCIS officer comments that she already did this. Gibbs gives her a condescending look, and merely says "yeah" and leaves for his interview. He could have made a more considerate remark to spare the woman's feelings.
Still, I liked the episode.