Single-action method of activating and exposing user interface of medical device

The invention provides a method for sequentially activating a medical device and exposing at least a portion of the user interface of the medical device to an operator, in a single action to be performed by the operator. The medical device, for example, an automated external defibrillator (AED), includes a housing having a user interface and a lid that is coupled to the housing. The lid, when closed, is covering at least a portion of the user interface. In one embodiment, the medical device further includes an on/off button. The button is configured such that, when an operator depresses the button, it causes a switch to close to thereby activate the medical device, and further causes the lid to open via a latch mechanism.