 Cowell made two escape attempts, reasoning that the chances of success were greatest if the attempt was made quickly, while still close to the front–line.However, the attempts failed and she was taken further into Germany, spending several weeks in solitary confinement at an interrogation centre for captured Allied aircrew, before being moved to the prisoner–of–war camp "Stalag Luft" I.

Cowell remained a prisoner for around five months, occupying the time by teaching classes in automotive-engineering to fellow inmates.In her biography, she describes the situational sexual behaviour shown by some of the camp's Allied prisoners, and her discomfort at being propositioned by prisoners who assumed she also wanted to take part in this.