I think my heart stopped a little bit at this bit (following as it had the part where John simply stops breathing as Sherlock holds him in bed):

He awakes to fire.

He looks over and John's already dead.

He starts crying.

Yeah, me too.

Seeing Sherlock lose his composure and his mind repeatedly, seeing him so abjectly human, just slew me. What a great mind-trip of a fic.