Opponent’s options: a12 plays, bingos on row 15 or row 1
Candidate plays: JUT i3, TIE 13a, CRIT a12
Potential plays on next turn: TOREUTIC a12
Subgoal: Maximize your expected equity over the course of the rest of this game.
Resolution: In Puzzle 12 you have no way of losing, so you may as well maximize your odds of scoring as much as possible. By playing TIE 13a (7), you give yourself a great shot at TOREUTIC a8 (99) next turn. Even if your opponent sees it, they might not block as there will also be potential bingo possibilities in the pool for you and they will try to bingo themselves.