Efron volunteered for the military in 1914 and by 1917 he was an officer stationed in Moscow with the 56th Reserve. In October 1917, he participated in the battles with the Bolsheviks in Moscow, then he joined the White Army and participated in the Ice March and defense of the Crimea, while Marina returned to Moscow hoping to be reunited with her husband. During that time, though, the relationship between Efron and Tsvetaeva was severely strained with very little communication between the two. Efron was particularly disenchanted with what he felt was a revolution largely unsupported by the Russian people, the expression of which inspired Tsvetaeva's "Daybreak on the Rails."