Black Mirror Season 4 - Episode: Hang the DJ
It is established at the beginning that the expiry date is revealed when both parties "press the button" on their devices.
Later on, when Frank is alone, he "presses the button" and the expiry date is revealed. Does this mean that Amy pressed the button earlier? If yes, then why is she angry at him for pressing the button, if she has done the same?
If Amy hasn't pressed the button, then why is the expiry date revealed?