A syringe assembly comprising: a fluid body (110, 410) that includes a side wall (112) that has an inner surface that defines a fluid chamber (115) to retain fluid and that has a first cross-sectional width , an open proximal end (119) and a distal end (111) that includes a distal wall (117)； a piston rod (160, 460) disposed inside the fluid chamber (115) comprising a distal end, a proximal end, a piston rod body extending from the distal end to the proximal end, and a stop (170) disposed at the distal end of the piston rod to form a fluid-tight seal with the inner surface (114) of the body (110, 410)； a retraction body (120, 420) disposed adjacent to the side wall of the fluid body (410), the retraction body (120, 420) including a wall having an inner surface (124) defining a chamber (125) of the needle, an open proximal end (129), an open distal end (121) that includes a barrier wall (122), an opening (123) between the wall (122) of the retraction body (120, 420) and the side wall (112) of the body (110, 410) for fluid that allows fluid communication between the fluid chamber (115) and the needle chamber and a needle cone assembly (140) comprising a cone ( 142) of the needle, a needle cannula (150) attached to the cone (142) of the needle, the needle cannula (150) being in fluid communication with the opening (123) and being pushed to move in a proximal direction ； and a firing element (190, 490) disposed inside the retracting and removable body (120, 420) inside the retracting body (120, 420) irrespective of the piston rod (160, 460), including the firing element (190, 490) a distal end (111), a proximal end (199, 499) and a body (192, 492) of the firing element, the body (192, 492) of the firing element extending from the distal end (111) to the proximal end (199, 499), a rupture element (494) disposed adjacent to the proximal end (199, 499) of the firing element (190, 490), the firing element (494) having an extension radially outwardly extending from the body
