[1] After the fall of Poland under the German and Soviet invasions of September 1939 he made the journey to France where the French Air Force was accepting Polish airmen and forming volunteer squadrons in Marseille.

[4] Mondschein was a member of the crew of Vickers Wellington Mark Ic (serial number “R1215”) on the night of 7–8 November 1941, attacking the German city of Mannheim.

680 in prisoner of war camp Stalag Luft III in the province of Lower Silesia near the town of Sagan (now Żagań in Poland).

[8][2] Mondschein cut out the concrete section to form the access point for tunnel "Dick" in Hut 122 and made a superb replacement which was undetectable.

[9] Housed in Hut 110 he bravely pushed on through bouts of depression when he spent nights unable to sleep and apparently accurately predicted his fate.

He was in the first group of twelve "walkers" who followed, they were led by Williy Williams and posed as a band of lumber mill workers on leave and included Canadian Jim Wernham and Poles Tony Kiewnarski and Kaz Pawluk.

[14][15][16][17] The four men were handed over to the Gestapo at 4AM on 29 March 1944 believing that they were to be returned to prison camp by road but near Jelenia Góra then called Hirschberg they were shot.

On 25 March 2012, the Czech Republic held a ceremony honouring these men and unveiling a plaque in their memory in the city of Most (formerly Brux) where they were murdered.