Here's a nice list of incidents where permit holders stopped shootings and/or other attacks. Just some ammunition to use against those who do not think guns are used by private citizens to stop violent criminals.
https://crimeresearch.org/2019/04/uber-driver-in-chicago-stops-mass-public-shooting/
https://crimeresearch.org/2019/04/uber-driver-in-chicago-stops-mass-public-shooting/