During 1935/36, Welker worked for the as an expert on intelligence operations. Between April 1936 and May 1937 she was employed at a Moscow Orthopaedic clinic. Then, between 1937 and 1941 she worked as a language teacher with the , later becoming a teacher at a Moscow military academy, relocating with the academy to Stavropol when the Hitler-Stalin non-aggression pact turned sour. During 1942/43, she became a graduate student at the "Comintern Academy" in Kushnarenkovo. That was followed by specialist parachute-agent training from which she emerged as an officer of the Red Army. During 1944, Welker worked as an educator near the frontline on the (centred at different stages on Kholm and Opochka). She was also involved in preparations for the advance towards the German cities.