Most people here in Canada support gun control. I've had conversations about self-defense with a few co-workers who say that one should call the cops when in danger. I gave them Detroit as an example; the average wait time for the police is just a few minutes shy of one hour!
Some time between when the shooting started at 2:02 AM and when the police finally entered the building around 5:00 AM, the terrorist shot 103 people (50 killed, 53 wounded). The news reports are calling this a hostage standoff, but the reports from people inside are that the shooting started right away. Based on the available reports, it appears that the police left an unknown number of shooting victims to bleed out for three hours before entering the building.
Think about that. A man with guns and ammo is slaughtering dozens of innocents while the police provide him three precious hours to do so. Calling the police did absolutely nothing for them. This is an argument for more guns -- not less.