Following their wedding, the young couple lived in Berlin until 1933. When the Nazi regime took power in the spring of 1933, they fled to Paris. The Rebbetzin was known to have taken university courses while also assisting the Rebbe with his.

In 1939, Germany triggered World War II by launching a blitzkrieg (lightning attack) against Poland. Chaya Mushka's father, aided by international intervention spearheaded by Americans, managed to leave early in 1940 while Germany was still officially at peace with the United States. Rabbi Yosef Yitzchak and some family members miraculously arrived in the United States on the last boat to cross the Atlantic ocean before the U-boat blockade began. Once in New York City, her father set in motion efforts to rescue his family from the impending cataclysm in Europe.

In May 1940, France was invaded by German forces and surrendered within four weeks. A French puppet regime led by Marshal Philippe Petain and Pierre Laval was established in Vichy, and the Rebbe and the Rebbetzin, like most Jews, fled to Nice in southern France, choosing to live under Petain's government rather than direct Nazi occupation in Paris and the surrounding areas.

In the course of their flight, there was a devastating bombardment. As people ran in every direction, she noticed an explosive shell heading towards a man next to her. Quickly pushing him to the ground, the Rebbetzin saved the man's life. Recounting this story the Rebbetzin characteristically said, "True, I saved his life, but for pushing a Jew one must do teshuvah."