It is not known why the prisoners of Gusen I and II were not exterminated "en masse", despite direct orders from Heinrich Himmler to murder them and prevent the use of their workforce by the Allies. Ziereis' plan assumed rushing all the prisoners into the tunnels of the underground factories of Kellerbau and blowing up the entrances. The plan was known to one of the Polish resistance organizations which started an ambitious plan of gathering tools necessary to dig air vents in the entrances.