...of cavers

Holloway refuses to follow them. For a while, he rants and raves, screaming profanities at a blue streak, until finally and abruptly, he just storms off by himself, vanishing into the blackness. It is another peculiar event which is over almost before it starts. A sudden enfilade of "fuck you's" and "shit-heads" followed by silence. [159]

[159] This is not the first time individuals exposed to total darkness in an unknown space have suffered adverse psychological effects. Consider what happened to an explorer entering the Sarawak Chamber discovered in the Mulu mountains in Borneo. This chamber measures 2, 300ft long, 1, 300ft wide, averages a height of 230ft, and is large enough to contain over 17 football fields. When first entering the chamber, the party of explorers kept close to a wall assuming incorrectly that they were following a long, winding passageway. It was only when they chose to return by striking straight out into that blackness - expecting to run into the opposite wall - that they discovered the monstrous size of that cavern: "So the trio marched out into that the dark expanse, maintaining a compass course through a maze of blocks and boulders until they reached a level, sandy plain, the signature of an underground chamber. The sudden awareness of the immensity of the black void caused one of the cavers to suffer an acute attack of agoraphobia, the fear of open spaces. None of the three would later reveal who panicked, since silence on such matters is an unwritten law among cavers." Planet Earth: Underground Worlds p. 26-27.

[House of Leaves, Danielewski, M. Z.]