So, I took the UHS hints to 9 of 12 because that was the first one that gave me some info that I didn't have. After 1/2 an hour I finally saw something but the puzzle never prompted me that it was what I was looking for. Also, when I backed out of it Darren said "that's not quite right". However, it was right and I was able to open the safe.
I thought the puzzle would let me know somehow when I hit on the right spot.
In fact, now that I solved the puzzle, I watched that portion of the video and finished reading the hints and it SHOULD have told me I solved it????