The flashlight is good advice in most situations. It would not have worked in Aurora. The theater was filled with smoke, so a bright light would not have blinded the perp and would only have pinpointed anyone carrying the light. As anyone who has driven a car through heavy fog can testify, using your brights just throws a wall of reflected light up in front of you, making it even more difficult to see.
I believe these ‘tactical’ flashlights have beams that DO cut through fog, smoke, etc.