 Nyora kupfuurira kweiyi ndima - Musi wa14 Ndira 1940 Rökker akaendeswa ku Luft-Nachschub-Kompanie 5 5th Aerial Replacement Company yakamira muGütersloh. Kubva musi wa4 Chikunguru 1940, akaiswa paBerlin-Gatow ne Schülerkompanie Flugzeugführer-schule Chikoro cheChikoro paAdvanced Flying School. Rökker akasimudzirwa kuva Gefreiter musi wa1 Gumiguru 1940. Ipapo akapedza kurovedza kwakakwirira pachikoro chinobhururuka pedyo neMagdeburg kubva musi wa20 March kusvika musi wa15 August 1941. Rökker akapinda Blindflugschule 5 muBelgrade, Yugoslavia yakatorwa, kubva musi wa15 September asati apedza kudzidziswa kwake paNachtjagdschule 1, pedyo neMunich musi wa1 November 1941. Munguva yekudzidzira kwake kwakanyanya, musi wa1 Chivabvu na1 Nyamavhuvhu zvichiteerana, akasimudzirwa pachinzvimbo che Fähnrich uye Oberfähnrich. 