He had finished basic officer training in 1936,[2] and holding the rank of Second Lieutenant in 1940 he continued to participate in battles north of Midtskogen, in Østerdalen.
The position was created by Oliver H. Langeland after some of the men handling weapon smuggling had been caught, most recently Mikael Hovhaugholen.
[5] Selvaag was asked to become weapons leader originally, and took over on 9 April 1945 when Øyen established a paramilitary base in Nordmarka.
All of this was highly illegal on Norwegian soil, and Øyen sometimes handled the weapons transport from production in Oslo to a testing site in Lommedalen.
In the summer of 1944, he was almost stopped in a German road control when transporting stenguns in a truck together with Asbjørn Pedersen and Bjørn Nicolaissen.
He was also a consultant for the Norwegian Armed Forces Medical Corps and lectured in disaster medicine at the University of Oslo.
He spent some time working abroad, notably in a field hospital from 1951 to 1952 during the Korean War, as leader of the Norwegian sanitary company stationed in Suez from 1956 to 1957 after the Suez Crisis, and as sanitary leader for United Nations Operation in the Congo (intervening in the Congo Crisis, Katanga) in 1961.
Hauge, Håkon Kyllingmark, Bjørn Rørholt, Elisabeth Schweigaard Selmer, Tor Skjønsberg, Anne-Sofie Strømnæs, Gunnar Sønsteby and Reidar Torp.