The first stab lacerated some artery or vein by his collar bone, and the subsequent stabs were shallow ones to his pectorals, after it seems he instinctively became alarmed at the depth of the first puncture. Blood immediately fills up his shirt from his collar bone laceration, and being drunk, he stumbles around while putting pressure on his superficial pectoral wounds, enabling the blood loss we see.
Sub-clavicular, possibly. That'll end it for you. Probably ended old Patesh, too.