Sarenka reentered the Warsaw Ghetto in January 1942, with two objectives. The first was to bear the message, as an eyewitness, of the methodical extermination of Jews in Punar, near Vilna; her fellow Jews had not heard these details until then. The second was to arouse and motivate rebellion against the Nazis from inside the ghetto. On her return to the ghetto, a group of youth united around her, some of whom she had instructed as a counselor. She detailed the Nazi massacre.