The player light, modified to have x amount of power that drains at a y-per-second rate (x and y can be changed with RTB prefs) that can be charged with an 'addLightEnergy [z]' (z being the amount of energy given to the light) and when the light runs out of energy it shuts off.
I'd prefer this to not be a tool and instead a 'Server_' add-on for the sake of convienency.
tl;dr:
Light acts like a flashlight, run out of power, find more power.