Hemostasis is the process of which involves stopping the bleeding in the event when bleeding occurs, either internally or externally. In this case, there might have been a cut (from the broken glass) and made the suspect bleed but stopped by the body's hemostatic mechanisms.
The hemostatic mechanism is as follows:
(1) Immediate local vasoconstriction to prevent further blood loss
(2) Activation of platelets and the formation of a platelet plug
(3) The coagulation cascade which ultimately forms a fibrin mesh to stop the bleeding
(4) Fibrinolysis to regulate the coagluation cascade and prevent thrombosis
