If, and only if, the staff of that store had drawn semi-automatic pistols (Loaded with hollow-point rounds) or pulled out, from under the counter, a shotgun (#3 shot recommended) and fired (From around the side, NOT the top, of a counter) it is possible-to-probable that those animals would have died or disabled before innocents were murdered r maimed to the "body count" reported. (It should be specially noted that the cited attack was in a neighborhood with police officers available within minutes, a response-time most uncommon in the USA).
The young lady stabbed to death in New York "fought back". She would have been able to save herself if she had fought back with: A razor sharp knife with a blade of four-plus inches; Or, A "pocket pistol" (Again loaded with hollow point rounds); Or, a small can of oven cleaning spray (Aim at eyes); Or, any of a wide variety of other improvised or converted weapons very suited for putting down dangerous animals.
Although I admit that "coincidence is not (Necessarily) causation" all Americans should note that the rate of violent crime in the USA has gone down as: The number of modern firearms, in the hands of private citizens, has very greatly increased; There has been a like increase in the number of American citizens holding permits/licenses to carry concealed weapons; AND,the number of States not even requiring such to CCW has been increasing.
Taking guns from law-abiding citizens exposes them to "a clear and present danger of death or great bodily harm" at the hands of ordinary thugs, those waging ideological wars and other criminals.