They came out better than the American engineers who helped build the Moscow Metro, most of whom did not even get an option to stay, but were shipped off to the Gulags beyond the Urals as soon as the project was done so they would not be able to disclose any of the classified or strategic aspects of it...there is supposedly an undocumented part of it that was built for the use of Stalin and other high Party officials to come and go from the Kremlin without detection, either in case of external attack or internal uprising. The Soviet-sympathizer-filled Roosevelt administration did absolutely nothing to spring them and very few survived.
