I finally figured out that the flashlight IS NOT on the gun like it shows on some pictures and previews. Its actually on top of Master Chief's Right Ear. How do I know this? Simple. On the 1st level, The Pillar of Autumn, before you pickup any gun, press the white button to activate the flashlight. It turns on, no gun intact. You can see this even more clearly Co-op, if you come up to MC and look at it. So there you go, no more speculation about where the flashlight really is located.
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