He played a major role in the negotiations with SS official Dieter Wisliceny to pay a ransom of $50,000 to the Nazi hierarchy which was one of the main reasons the Slovak transports to Auschwitz stopped in early 1942.

The same year, he and his wife fled to the Slovak State with their young son to escape persecution in the German-occupied Protectorate of Bohemia and Moravia.

[1][4][5] Steiner played a major role in helping the Working Group bribe the Judenberater for Slovakia, SS official Dieter Wisliceny.

[6] Against the wishes of Rabbi Michael Dov Weissmandl, another member of the Working Group, Steiner provided the Slovak police with evidence against Hochberg, who was arrested on charges of bribery and corruption in November 1942.

[8][9] At this time the Working Group was trying to gather funds for the Europa Plan, a proposal to halt deportations to extermination camps in the General Government in occupied Poland for $3 million.

[10] Historians have concluded that the Nazis did not intend to release a significant number of Jews from death,[11][12] but the Working Group's leaders believed that the offer was genuine.

However, due to Allied restrictions on currency transfer, the funds had to be sent illegally, and the Working Group did not receive the money the Nazis demanded in time.

After the liberation of Slovakia in early 1945 by the Red Army, he resumed his architectural career and also ran a rehabilitation center for Jewish children with funds provided by the Joint Distribution Committee.

[1] A 1999 documentary by Brad Lichtenstein, André's Lives, chronicles Steiner's return to Slovakia with his sons to discuss his wartime experiences.