 Although Haase had much more surgical experience than Schenck, he was greatly weakened by tuberculosis, and often had to lie down while giving verbal instruction to Schenck.The large Chancellery cellar led a further one-and-a-half meters down to an air-raid shelter known as the "Vorbunker".The "Vorbunker" was connected by a stairway down to the "Führerbunker", which had become a de facto Führer Headquarters.