Revier was a term used in Nazi camps to designate the medical facility for inmates.
Death was to be expected immediately upon entrance to a revier: An "insufficiently" sick person could be classified as malingerer, who was avoiding labor.
Even being admitted into the revier gave little hope: while the medical personnel (inmates) could be highly qualified doctors, they could not offer any help beyond very basic first aid.
In addition, rations for the sick were lower than for the inmates who could work and no hygiene was maintained.
Finally, at any moment the residents of a revier were subject to extermination for various reasons (e.g. a threat of an epidemic, due to overcrowding or deemed incurably sick).