[nonsporting]

Given the bedlam in the Aurora theater - a tear gas cloud and a masked gunman with multiple weapons spraying bullets - it seems highly unlikely a regular citizen could have disrupted the killer's plot. My guess is the only ones who believe they actually could have stopped the guy are probably influenced by too much television or Hollywood.

No. Those of us with training understand what is possible and what is not.

The shooter can only operate one gun at a time. Weapons do not "spray" bullets. Regular citizens can do remarkable things.

The muzzle flash of the AR15 in the darkened theater would reveal the bad guy's position. The good guy should shoot at this flash when the opportunity arises and move obliquely closing the distance. Other tactical opportunities may present themselves. Have a plan. When and if that plans goes to hell, create a another plan. If one gives up, he may die (or allow others to die).

[houeto]

The muzzle flash of the AR15 in the darkened theater would reveal the bad guy's position.

Exactly, and several citizens hitting his spineless, chickensh!t a$$ would probably have made him crap his britches and start crying.

Lives could have been saved. I'll never believe otherwise.