this goes back to the ages old problem of, "In Star Trek, the transporter killed you every time" We have this almost social idea of Body Continuity. As long as there is the same body the entire time you are still you and still "alive". A scarier truth is that all it takes is a decent change to how you brain is structured (bullet, railroad spike, fork through the skull) and you can very suddenly for all intents and purposes be a different person, with the same or similar memories but essentially different patterns of behavior. Metamorphosis may not save you, it might kill the person you were just as if you made a copy and burned the original. Further down the rabbit hole, just how different is your brain now from and instant ago, and your brain versus your brain with the addition of a few ball bearings or other random matter. The person you were an instant ago is just as dead as the original who gets destroyed and you are the copy.