 In such circumstances, others, meaning to save themselves at the gas chamber's threshold, betrayed the identities and "revealed the addresses of those members of their race still in hiding".Once the door of the filled gas chamber was sealed, pellets of Zyklon B were dropped through special holes in the roof.Regulations required that the Camp Commandant supervise the preparations, the gassing (through a peephole), and the aftermath looting of the corpses.