You can't predict an elevator's behavior. If you observe an elevator from the outside and don't see which buttons are being pressed, you will really think the elevator has a mind of its own. It travels to the first, second or third floor, based on cues it perceives from its environment (someone pressing a button).
Elevators respond to button presses, but not to screams, in the same way that humans respond only to environments that interest us (for which we were innately designed to be interested), and we ignore all others (e.g. we can't detect magnetic fields the way trout can).
Elevators are constructed from a set of design blueprints. Humans also develop from a genetic blueprint. If we have Free Will, then why don't other designed entities with internal memory and programming to respond to environmental inputs also have Free Will?
Humans are free to do what we're designed to do (what we want to do). Free Will is simply the freedom to follow your design... which is not really Free Will is it?