Avigdor served in a forced labor unit, managed to escape, reach Budapest and arrive at 17, Wekerle Sándor Street which was a branch of the Swiss consulate and one of the centers of the underground youth movement operations. Avigdor joined the underground activities and was one of the founders of the “Hospital” on Vilmos Császár Boulevard located in the cellar of the Zichy cinema to provide a hiding place for the activists. Thanks to his Aryan appearance (light hair and blue eyes) and wearing an overall with the Nazi insignia, Avigdor went every morning to the Vígszinház Theater in order to receive the daily password which was needed for walking freely in the city streets. He then gave the password to his friends on Wekerle Street. After the liberation Avigdor continued his activities in the movement and provided food for children who had survived. In an effort to make aliya, he crossed the border into Romania and arrived in Bucharest where a hahshara unit was being set up. From Romania he travelled to Yugoslavia. In Belgrade he was informed that his sister, Leah, had returned from Auschwitz and was in Budapest. He traveled back to the Hungarian capital and found his sister in a severe condition. He helped her to recover and enrolled her in the movement. Avigdor lived in Herzliya.