Stun Gun, Anyone?

"On November 4th, the manager of a NY café was stabbed to death by a delivery person who was just fired. While the manager was known for being generous and flexible, the assailant became enraged when he was told he was being let go in the back of the restaurant. The 26 year old manager staggered to the tables area that was filled with customers with the knife still sticking out of his chest. The assailant fled and evaded capture." I wonder how much difference a stun gun or pepper spray in the hands of this manager would have made? In Aukland, NZ, this: "The Auckland-based Framework Trust in New Zealand provides mental health services for mentally and intellectually disabled people as well the dangerous. A young man who is patient struck a staff member in the head without warning on October 4th while they were out in public. The worker was not responsible for watching the client but was standing close by. The staff member was hospitalized with serious head injuries and concussion. The same client had struck another employee in the head with a cricket ball which then required stitches. Workers and family members are concerned about the safety and security of their positions. The government's Occupational Safety and Health department is holding an investigation." Again I wonder: what difference would a stun gun or pepper spray in the hands of this victim have made?