In Puzzle 10, it is very difficult for your opponent to play a bingo. The main concern you have is to control the bingo lines and space on this board, and to limit your opponent’s bingo potential.
The most dangerous bingo line is the threat of column A. How can this be? Well, your opponent has the opportunity to make a very dangerous hook with _IX and _AX words, creating a difficult-to-block S hook that not only scores well but opens the top of this board.
Since you have a fairly commanding lead, you don’t want to give your opponent to increase the entropy of this board. Thus, blocking by playing UKE 10a (16) is best, limiting the board and controlling your opponent’s short term options and preserving the long-term entropy.