Flegel, a high noble related to Duke Otto von Braunschweig, played a role in the imprisonment and torture of Wolfgang Mittermeyer in 486 Imperial Calendar. Despite failing to extract information through interrogation, he attempted to beat Mittermeyer personally. However, when Mittermeyer accused him of cowardice for attacking a manacled man, Flegel released his handcuffs and fought him fairly. Although he was easily defeated, he called for his companions to shoot Mittermeyer. This plan was thwarted by the personal intervention of Admiral Reinhard von Müsel at the request of Rear Admiral Oskar von Reuenthal.