A pressure control and leak test system for a medical instrument includes an upper housing, a valve member, and a vent opening arrangement. The upper housing includes a cavity for fluid communication with an interior of the medical instrument and an aperture in fluid communication with the cavity. The valve member includes a stem within the aperture and a cap section. The cap section includes a proximal-facing end with a bottom surface and a distal-facing end. The vent opening arrangement includes a first feature of the cap section and a second feature on the distal end of the upper housing. The valve member rotates relative to the housing causing the first feature and the second feature to seal the cap section with the housing in a first position and separate the cap section from the housing in a second position.