Hello @The_Beaticus,
neither finished nor leaves are javascript-events ... sadly ...
anyway: here (onIdle.hype.zip (25.2 KB))
is something that may or may not work. it's not well tested.
setup: set the time of inactivity in the head, set the name of the scene that should be displayed when inactivity occurs ...
//to set: checkInterval = 1000 equals one second and name of idleScene
var checkInterval = 10000, /*10 seconds*/ idleScene = "Pause"