Proper holsters and proper cases**
provide the only reasonable way to avoid violating Rule 1 while carrying a loaded gun.
If you're carrying a loaded gun without one then it's virtually impossible not to violate Rule 1.
As far as I'm concerned, the person involved intentionally violated the first rule of gun safety with a loaded gun in a crowded area by carrying it without a proper holster.
**A proper holster/case covers the trigger/triggerguard and makes it totally impossible to fire the gun until it is removed from the holster/case.