This means that I was working on last Friday's crossword on this past Monday or Tuesday. (I'm pretty sure I've waited long enough to mention this that I won't spoil the puzzle for anyone.) The theme was "three doctors": each of the key entries was a string of three well-known "doctor" names (Kildare, House, Quinn, Quincy, No, X, Zhivago, etc).
In the bottom key entry, I saw that the middle name would be short and started with a W. There's a Steely Dan song called "Doctor Wu", so I had that possibility in mind. The crossing term was an abbreviation for one of the books of the Bible; I'm never able to get those, because I don't know the names of about half those books and because the abbreviations the puzzlemakers go with are often terrible. My only option was to get the final "doctor" name to confirm the length of the middle one.
But the final name was shorter than I expected, leaving me with a three-character name to finish. And then I determined that the last character of the middle entry was O.
So I guessed ... Woo. And I thought the crossing entry looked wrong, but I didn't even suspect the correct answer until I checked the answer key.