As the Germans engaged in Operation Case White, Savić maintained his position with the Partisan Supreme Command, but fell out of favor in July 1943, and was demoted for reasons that are unclear. He nevertheless participated in the second convention of AVNOJ in November the same year, and in April 1944 was again promoted in the military, and sent on a mission to the Soviet Union. He arrived in Moscow where he also immediately engaged in scientific work with Pyotr Kapitsa and others, on the topic of liquid helium on extremely low temperatures. He returned home in October 1944 to liberated Belgrade, where he continued his socio-political activities as well as work on the restoration of the University. After the war had ended, he had another short stint in Moscow, but returned home to work on founding of an Institute of Physics, and was also promoted to a member of the Serbian Academy of Sciences and Arts in 1946 and 1948.