A door securement system for a protective case for housing a mobile device is provided. The protective case comprises a top shell that covers a top surface of a device and a bottom shell that cradles the back of the device. Where upper and lower backing elements are used that meet at a parting line along the outer (exterior) surface of the bottom shell, a locking mechanism may be used to pull the backing elements together and hold them in place. A multi-hinged door is positioned along a portion of the protective case to allow access to ports of the mobile device. The door has open, shut and sealed configurations.