These weapons were used by European forces during the interwar perid of the 1920s and 1930s and through the Second World War period (1939-1945). They are German weapons because the action takes place in a concentration camp inside Germany.
“Add Image Cartridge: 9x19mm Parabellum. Feed: 32-round Snail Drum. The MP 34 is a submachinegun...MP-34 Submachinegun