So I just received my Surefire G3. I was bummed thinking it was 200 lumens. turns out it's only 105 but can go up to 200 lumens with the purchase of the P91 lamp. This is from the Surefire website.---- Description P91 The ultra high output P91 Lamp Reflector Assembly gives you nearly twice the light of the P90 - 200 lumens with a 20 minute run time. Fits: 9-volt incandescent flashlights with a 1.25" bezel Features 200 lumens for 20 minutes Fits in the SC1 Spares Carrier for field deployment Now does this mean with the juice it's pulling from the batteries it will run only 20 minutes until batteries die? Or does it mean the lamp itself will die after 20 total minutes of usage?