The epilogue of the show makes it very clear that the three survived and at the time of broadcast two were still alive. Also, I believe the Soviet authorities

The epilogue of the show makes it very clear that the three survived and at the time of broadcast two were still alive. Also, I believe the Soviet authorities at the time may have incorrectly believed that a large explosion was possible - in that respect the show may be correctly repeating a mistake that was made at the time.