Kwon Hyok, a former head of security at Camp 22, described laboratories equipped with gas chambers for suffocation gas experiments, in which three or four people, normally a family, are the experimental subjects. After the people undergo medical checks, the chambers are sealed and poison is injected through a tube, while scientists observe from above through glass. In a report reminiscent of an earlier account of a family of seven, Kwon claims to have watched one family of two parents, a son and a daughter die from suffocating gas, with the parents trying to save the children using mouth-to-mouth resuscitation for as long as they had the strength.