 His saboteur activity included to prepare the sinking of "Tirpitz", but the plans were never realised as the ship had left the Trondheimsfjord in early 1943.Sørli commanded Gjems-Omstad to a spontaneous assassination of Nazi collaborator Ivar Grande after spotting him incidentally, but Gjems-Onstad aborted after noticing a division of Russian POWs, fearing for what in turn might happen to them if he went through with the assassination.Some days later he again plotted to assassinate Grande together with Sørli and Ingebrigt Gausland.