KCee Scheyer was instructing him to pass it. It was a planned zone-press breaker rhat the coaches had worked out based on tape they saw.
UConn made a pretty big mistake not fouling Sarr when he got the ball near the baseline. That was their surest way to a win, and Hurley can be seen in the footage instructing them specifically to foul him, but they didn't.
Playing keep away successfully wins Duke the game once they failed to foul Sarr, so lt wasn't really the wrong move to advance the ball, just wasn't executed. If Cayden had thrown the pass before the dribble it would likely have been successful. If he had thrown it higher it would have been successful. There were a hundred ways for Duke to win the game and only one way to lose it, which is what happened, with the perfect deflection that was easily handled, and the perfect shot.
If they played it out from the same place 50 times UConn would win the game once. Twice at the most.
It was just another one of those magical March Madness moments that makes everybody interested in the tournament.