The imprisonment of Molotov's wife did not take place just before Stalin's death, but some years earlier, well before the action of this play begins.
The Soviet Government showed its displeasure at this production by shutting down the CBS News bureau in Moscow. From then on, other Western news bureaus in Moscow were circumspect in their reporting on the USSR. A few years later, they received word of an anti-Soviet uprising in a remote city. Not wanting to suffer the same fate as CBS, they sat on the story rather than incur the Kremlin's wrath.
At the time the play was first shown, the exact circumstances of Stalin's death were not known in the West. It was later confirmed that he had not suffered a stroke in his office in the Kremlin whilst in the company of several senior officials, as the play depicts, but whilst alone in his dacha at Kuntsevo, outside Moscow.
This episode takes place in 1952.