To violent Alzheimer's patients?
How much of a physical threat could he pose to couple of cops?
That's one of the things we don't know. But if the police (or facility staff) had wrestled with the guy trying to get him back to the facility, and he fell and hit his head and died, would you still consider it murder? If not, why not?
Neither physical restraint nor tazing is supposed to kill anyone, so how is one different from the other?
That question alone exhibits your ignorance.
Have a nice day