That's how long an 18yr old w/ her 3 month old baby was on the phone w/ 911 while armed criminals were trying to break into her home.
Had she not been armed or if she had been restricted to the standards of Washington DC, etc keeping the gun disabled and w/o ammo, she and likely her baby would be dead right now.
And groups like the Violence Policy Center, Coalition to Stop Gun Violence, Mayors Against Illegal Guns and the Brady Campaign prefer that option to her protecting herself. They ALL submitted briefs defending DC and Chicago's gun laws.
Next time a gun control advocate tells you you should rely on the police and that a gun is more dangerous than a criminal. Ask them to start counting. Then start tapping them on the forehead to the count. See how long it takes them to tell you to stop. Ask them what they would do if a criminal were doing something a lot more invasive than that to you or your loved one for 21 minutes while they waited for the police to show.