I've completed the puzzle including the endgame, but I'm worried that I've misidentified one of the three extra words that lead to the top row. In 3d, I have "are" as a word that has to move to the left to after "ten". This gives ENTREA after "lowering heads" and adding T ("no longer to") gives ENTREAT. This has already been noted in previous replies.
However, I also have one of the three extra words in this clue, and my reading of the preamble suggests that the three extra words should be in "another three clues", not in the ten clues where a word has to be moved. This is certainly the case for the other two extra words, but I can't see an extra word in any of the other clues that don't have a moving word. On the other hand, the last word of 3d can be deleted without damaging the clue and is a synonym for the last of the three words forming the top row.
Am I misinterpreting the preamble, or am I missing something obvious?