Imo, easily the most beautiful piece of music ever to come out of any game, anywhere. Haunting, it brings a sadness to the scene where Joel carries Ellie from the surgery room... a kind of despair that gets under your skin. At first, you don't know why you're feeling so sorrowful... as if Ellie is surely going to die, and probably you too. That's the power of the music.
Notes:
This clip starts at 1:20 of "All Gone [No Escape]" (track #20 in the OST). "Ellie's Theme" is my name for the piece.
In the actual game, the 1st ~10 seconds of the music that plays while Joel carries Ellie from surgery are taken from the very beginning of "All Gone [No Escape]", then it jump-blends into ~1:38, and continues to the end.
(I claim no copyright ownership whatsoever to any of this material.)