Gathers' first sign of trouble came on Saturday, December 9, 1989, when he collapsed at the free throw line during an LMU home game against UCSB.

He was found to have an abnormal heartbeat (exercise-induced ventricular tachycardia), and was prescribed a beta blocker. However, Gathers felt that the medication adversely affected his play, and he soon cut back on his dosage.

On Sunday, March 4, 1990, he collapsed again with 13:34 left in the first half of a West Coast Conference tournament quarterfinal game against Portland, just after scoring on an alley-oop dunk that put the Lions up 25–13. He attempted to get up, telling the trainers, "I don't want to lay down!", then shortly after stopped breathing. He was declared dead on arrival at a nearby hospital at the age of 23. An autopsy found that he suffered from a heart-muscle disorder, hypertrophic cardiomyopathy.

Following his death, Gathers's parents eventually sued LMU for $32.5 million. The school settled out of court for $1.4M.