In those final few seconds, after the spell had worked its way into his heart but before he slipped forever through the veil, Sirius Black saw everything.
He saw himself, aged eleven, nervously awaiting the sorting, begging not to be in Slytherin. He saw the owl that brought the Howler from his mother- screaming of the shame he had brought on them. He saw James, Remus and Peter, young and unbroken, laughing at some ridiculous prank. Snape's hair a flashing purple.
A scowling Lily Evans, then a smiling one. Her green eyes sparkling with mirth and mischief. Them same eyes, big and round on her baby. Baby Harry, blowing raspberrys and chuckling as he pulled Sirius' hair.
Remus, howling in pain as Moony took over. The crumple of a Death Eater taken down by Sirius' wand. Harry's face twisting in shock and relief as he realised Sirius had come to save him.
Everything Sirius was, had ever been, was jumbled up in a chaos of love, hurt, laughter, pain, sorrow and unashamed joy. Every time he had been scared, every fight he had ever fought, every love he had ever loved was there. Dancing before his eyes as though to tease him. He would never feel those things again. He would never be again.
And though he heard the desperate, almost feral cries of Remus and Harry there was nothing he could do. No way he could say goodbye. Or thank you. Or I'm sorry. Time was up. It really had ended like this. The unfairness, the sheer aching sadness of it, took its place in his very bones.
"It seemed to take Sirius an age to fall: his body curved in a graceful arc as he sank backwards through the ragged veil hanging from the arch".