The team pulls up a hologram of the perpetrator, Renard, and discuss how a bullet got lodged into his head. They mention that the bullet is slowly moving through his medulla oblongata and killing off his senses: touch, smell, and pain. They state that he is getting stronger every day until the day he dies because he lost these senses.
Joel and Clementine's relationship is about to be erased forever, and it might never be repaired. In Joel's mind, he goes back to the moments where things were perfect and beautiful, where that ideal version of his partner would have understood, and together they could have saved the relationship. In this clip, Clementine is Joel's imagination, his perception of who he thinks she is. He knows her so well that she is perfectly painted in his mind.