It would be interesting to see how everyone reacts to an instant death switch or ability to set your own death date lower or higher than your natural life expec

It would be interesting to see how everyone reacts to an instant death switch or ability to set your own death date lower or higher than your natural life expectancy without society having control over it. Not only people want control over their lives but once they get it, they will naturally want to control others. I wonder about the ethical complications. If someone is dying from heart attack but you can save him every time he goes through it, will you force that even if the person want to die via heart attack? At what point do you differentiate between suicide or ability to quit it?