An embodiment of a device for expressing blood from a wound site formed in dermal tissue is constructed in the shape of a cap removably mounted onto a lancing instrument. The chests employ unique locking systems tailored for use with such pivoting drawers, where an actuator is operable to pivot a blocking member inside the chest between the drawers and a wall of the surrounding housing about a vertical axis into a position interfering with motion of a feature projecting outward from one or more drawers under attempted pivoting thereof. A transfer medium is passed through the image formation stations to form color images in a tandem fashion. The non-performance critical exceptions are routed to a non-speculative exception handler that only resolves exceptions when the excepted instruction is certain to execute in an actual path of the program flow.