The sentence having taken account of the time spent in pretrial detention, he was scheduled for release in 1940, but instead he was taken into "protective custody", and spent the next two years as an inmate at the Sachsenhausen concentration camp. At Sachsenhausen there was already a core of communist activists among the inmates who were able (discretely) to welcome another political soulmate. Across Germany, as war deaths took their toll of manpower, administration of daily life in concentration camps was increasingly delegated by the camp guards to trusted inmates; the decisions of "friends" meant that Selbmann was set to work in the vehicle repair shop of the camp brick making operation where, as he later recalled, the work was "not hard or especially dangerous". In November 1942, however, he was moved to the Flossenbürg concentration camp, which supplied labour to local quarries, set in mountains adjacent to the border with what was at that time known as the Sudetenland. According to Selbmann's own recollection the transfer to Flossenbürg involved eighteen prisoners who had been placed in solitary confinement the previous month as a response to their political activities. The move was implemented on the orders of Reichsführer Heinrich Himmler himself: it represented a punishment "for building [Communist] cells in the camp [at Sachsenhausen], organizing revolutionary work, and privileging political prisoners". During what turned out to be the final weeks of the war the Flossenbürg camp was closed down and Selbmann was transferred again, this time to Dachau in the suburbs north of Munich. At the end of April 1945, as the authorities raced to clear the concentration camps of their inmates ahead of the arrival of the invading armies, he was sent out on one of the infamous death marches. He managed to escape and made his way back to Leipzig.