The day after the explosion , Organisation Todt workers was assigned to clean up the debris and wreckage . On 30 March at 16 : 30 the torpedoes from MTB 74 , which was on a delayed fuse setting , exploded at the old entrance into the basin . This raised alarms among the Germans . The Organisation Todt workers ran away from the dock area . German guards , mistaking their khaki uniforms for British uniforms , opened fire , killing some of them . The Germans also thought that some Commandos was still hiding in the town , and made a street by street search , during which some townspeople was also killed .