A medical device includes a device housing and a door mounted to the device housing. The device also includes a first magnet mounted to the door, wherein magnetic force applied to the door exerts a moment on the door, and a second magnet mounted in the housing and positioned to hold the door shut by magnetic interaction with the first magnet. In addition, the device includes a user-movable mode-changing mechanism attached to a third magnet, and arranged to hold the third magnet out of proximity with the first and second magnets when the device is in a first mode, and to move the third magnet into proximity with the first and second magnets when the device is in a second mode so as to expel the first magnet away from the housing and open the door to expose items positioned behind the door.