During the less hectic periods in his life on the front line he was able to complete a dissertation for his habilitation, and during a period of leave in 1944 he received the qualification from the Humboldt. During the closing months of war he served on the western front, advising an army company on toxicology issues. After that, early in 1945, he found himself back in the Bodensee area, summoned to work at the massive , on a secret project which involved arming grenades with highly toxic battle chemicals. War ended in May 1945, and together with the facility commander at Urlau, in defiance of orders from the top that the entire facility should be blown up, Jung was able to mediate its bloodless hand-over to French troops.