Yes, people are feeling that they need to step up and become vigilantes, more or less. I don't agree with this, but it's a result of escalating gun violence. More guns will never stop gun violence; it will only create more. People are operating in fear mode and taking matters into their own hands. Unfortunately this is creating more chaos and violence.
No, gun violence is not forcing citizens to perform the function of security guards and police. Gun violence is created by more people having the option to own guns, regardless of any background they may have with crime or violence. Those who are able to stop gun violence by carrying a firearm are far outnumbered by gun violence crimes that are stopped by appropriate personnel, and that statistic is dwarfed more by those who are able to get away with gun violence. The only good that comes out of those stopping gun violence with their own firearm is that it gives them more of a reason to continue carrying that weapon.
Gun violence is not forcing people to Police or Guard anyone or anything. As citizens we are only responsible to guard/protect ourselves and our loved ones and sometimes even total strangers (as in the case of this Waffle house) BUT this in no way means carrying a gun at all times, this is not the wild wild west, there are other ways to stay safe and 911 is there for a reason. In a society where everyone carries a gun anarchy rules because everyone will be of the mindset they can solve every issue no matter how small by shooting it up.
The vast amount of easily obtainable guns found in the US allows many people, both civilians and criminals, access to guns. Although in this instance the crime was stopped, civilians are not trained to make the decisions of when and how to shoot a criminal. If these sort of instances are acceptable, more people will die each year as a result.