Oh wow reading this made me smile :D Thank you! There is actually an auditory indicator when your meter's getting low. You can kinda hear a slight reverb effect going on when it's under 70%, the lower the more noticeable. As for the guard's flashlight keeping your meter full, there's a secret location in the 3rd level that uses that exact mechanic. You can't run anywhere with the guards cause the navigation area is sort of limited, but there's a path they can take that leads you there :) It's nothing special but it exists.
Thank you again for playing and making my night! Definitely checking out your game when i got some time! :)