“Considering the killer is said to be 72 years, he put up a surprisingly spirited fight against this young man (who, it appears, was simply trying to disarm the killer, not subdue him). Too bad nobody else stepped up to tackle the killer after he was disarmed.”
The man was fighting for his life. His goal was to keep the gun away from the killer.
even frail old women have some strength if they get mad enough.