Erik Bjurström wrote an interesting narrative about exploring the underground lake of Ain Hith, Saudi Arabia:
...I began to feel uneasy; if we lost visibility now, our situation would be dangerous. My partner had considerable less diving experience and seemed unaware of the danger. The situation rapidly went from bad to worse. Before I could signal to him to turn back, he started to crawl through the opening making violent kicks with his fins. In an instant all visibility had gone. We were left groping in a milky soup. There was no way of judging direction. Only the rope leading upwards, white in the torch-beam, offered a chance of returning safely...