Every room resets. Remember I told you that? Every room reverts to its original condition. Logically, the teleporter should do the same. Teleporter. Fancy word. Just like 3D printers, really, except they break down living matter and information, and transmit it. All you have to do is add energy. The room has reset, returned to its original condition when I arrived. That means there’s a copy of me still in the hard drive. Me, exactly as I was, when I first got here, seven thousand years ago. All I have to find is some energy. And all you need for energy is something to burn.
How long can I keep doing this, Clara? Burning the old me, to make a new one?
Heaven Sent, my favourite Capaldi Era episode as requested by @lullapiee.