He was first imprisoned at Oflag XXI-C in Schildberg in the German-annexed "Reichsgau Wartheland". While interned at Oflag XXI-C, Løken shared a room with Colonel Johannes Schiøtz, with whom he had attended the Norwegian Military Academy close to four decades earlier. Løken and Schiøtz were roommates at Oflag XXI-C from 6 January 1944 to 19 January 1945, when the Norwegian prisoners were sent on a one-week forced-march on foot and by train to Oflag III-A in Luckenwalde, Germany. On 24 January, five days into the journey, Løken was transferred to a hospital train carriage, suffering from ill health. The Norwegian prisoners of war remained interned at Oflag III-A until their German guards abandoned the camp on 21 April 1945, with Soviet forces arriving the next day. On 10 May 1945, two days after the end of the war in Europe, the Norwegian prisoners left Luckenwalde, reaching Norway in several groups in late May/early June 1945. Løken arrived in Oslo on 28 May 1945.