I have reached the point now that I consider Ms. Carroll to be one of the shining stars of puzzle creation at the NYT. When I saw her name attached to this puzzle, I knew it was going to be a fun solve, and I was right.
I knew something was up from 1A: Extremely slow speed (SNAILS[PACE]). I immediately thought of the answer in question, but wondered how to make it fit. Would there be a rebus? But no, when I looked at 6D: Elbow room (SPACE), I saw the answer turned the corner. Then I hit the middle of the puzzle and got the revealer clue at 40A: Seedy hangout ... or a hint to finishing four Across answers in this puzzle, and had that wonderful "Aha!" moment. DIVEBAR! Or in this case, four instances where an answer turns the corner, and the part that goes down can be put before the word "bar" to make a standard phrase or word.
It was fun to search out the other three. Because of the way the trick works, there were only five other possible places (the two not used come at 7A and 30A, not counting the revealer itself). How cleverly Ms. Carroll has worked this out, so that each part going down can be clued on its own, thus not revealing the locations through a "-" clue. Even better, the portion of the answer going across can also stand on its own. Also, look at the four examples: SPORTS as part of TRANS[PORTS], MINI as part of GEM[INI], and CROW as part of ESC[ROW]. Each one is very nicely hidden in its parent word, never carrying its final meaning in the original word.
Meanwhile (just to gush some more), the rest of the puzzle shines as well. There are two long down answers in ARABIANSEA and ANTITHESIS that are wonderful. I love MUSHROOM in the sense of growing.
And finally, the cluing. You get misdirects, like 2D: It flows past Memphis (NILE) - not Tennessee. You get silly stuff like 29D: One crying "Uncle!," maybe (NIECE). How about the excellent and simple 44A: What junkyards do (REEK)! And even the QMCs are nice, like 7A: Have a sudden inspiration? (GASP).
When I have fun like this, I can overlook stuff like IOS, TUE, even UNTER. Fun puzzle today.