It was because of his reckless behavior last season that no one believed DeLuca when he thought he spotted signs of sex trafficking because of a young patient, and why DeLuca felt the need to go after the woman he felt was the culprit when she returned, leading to his death when he was stabbed by one of her accomplices.
The loss of DeLuca has hit fans hard, especially since the accomplished doctor was only recently able to come back from the mania that was starting to control his life, after finally getting treatment for bipolar disorder.