The men used tools they have underground to establish a light source and to power their head lamps – after food and water sources, establishing reliable access to light is critical to staving off psychological deterioration.
“The most important thing, aside from keeping physical needs satisfied, is to help them keep a positive frame of mind,” Dr. Suedfeld said. “Darkness is disorienting. It leads to uncertainty. That leads to anxiety and fear.”
And that leads to the dark side! Wait -- that's circular.
Anyway, hopefully the officials down in Chile have some good consultants available to advise them on how to keep tensions to a minimum amongst the trapped miners. Their situation is precarious enough without them fighting all the time.