Tightly gripping his jacket, The Doctor could feel his two hearts racing, pounding harder and faster then ever, as every cell in his body was beginning to be rewritten. There was a distinct pain in his core, it felt like something had lit a fire inside him.
No matter how many times he had experienced this process he could never quite get used to it. He couldn't help but cry aloud as he thought of all the things he had experienced during his time in this body. He wasn't ready to give it all up, there was still so much to do, so much to see. He knew that nothing would ever be the same, he would become a new version of himself, old memories in a new looked around the room and thought of all his past regenerations, remembering all of the good times he had. No matter how hard he tried he also thought of the bad times, his lowest points, and all of his friends he once had. Everybody dies but he knows this better then anyone else.
His regeneration was about to reach its peak, he could feel it in his stomach growing. He sobbed as his body started to glow a golden yellow, the room was engulfed in a brilliant light. He fell to the ground as he became a new man once again.