If the Germans had taken either Moscow or Stalingrad (or both), would Stalin have ordered a Second Great Purge of his officers once he learns of the fall of said cities due to his paranoia akin to what he did in the "Anglo/American-Nazi War"? If so, how much would the Soviet officer corp have been gutted due to said Second Great Purge? Could warnings that they could be purged have led to a military coup against Stalin?