For much of the war he was tasked with taking out targets attacking besieged Leningrad, and in early 1943 he participated in the breakthrough of the blockade; over the course of 13 sorties he took out ten vehicles, an ammunition depot, four railway cars, four bunkers, and killed over 100 enemy combatants.

While leading a group of four Il-2 aircraft on an attack over a stretch of railroad on 19 March 1943 they took out 15 railway cars and caused a significant delay of traffic on the line.

During a mission on 21 February 1945 he was badly injured after his Il-2 was hit by an anti-aircraft shell; although he was able to make an emergency landing in Kreuzburg, the severity of his injuries resulted in him being confined to the hospital for the remainder of the war, where he underwent a craniotomy.

[3] Eventually Mylnikov was released from the hospital in August 1945, but since he was unable to return to flying for health reasons he had to leave active duty for the reserve in November.

He lived for the remainder of his life in Moscow, where he died on 26 September 1979 and was buried in the Vagankovo cemetery.