I will respond to this section: "Think how different the outcome would have been in these mass shootings if one legally armed civilian had taken out the mentally ill person after the first shot, instead of waiting for minutes or hours for police response? How many lives could have been saved?!"

Yes, that will prevent more victims, but I thought there would be no shooting if there were no weapons. It's certainly much better..but that might be just a different perspective..no problem ;)