Stalin purged 20,000,000 prior to WWII, of which half died in labor camps. Almost 10% of the Command structure of the Military was purged. All the old Bolsheviks were put in show trials and executed.
So much for inspiring loyalty. Staling did not and could not stand anyone having a larger presence than him. Just look what he did to Georgi Zhukov, who beat the Germans and won the war for him.
Ed
One of the best war movies I’ve ever seen was “Brest Forest”. At the end of the movie we learn about the fates of the heroes of Brest Forest. The main character, Gavrilov, we learned served 10 years in prison after he was liberated from German captivity.