He did not know why he was doing it, why he was approaching the dying man: He did not know what he felt as he saw Snape’s white face, and the fingers trying to staunch the bloody wound at his neck. […] A terrible rasping, gurgling noise issued from Snape’s throat.

“Take it…it…Take…it…”

Something more than blood was leaking from Snape. Silvery blue, neither gas nor liquid. […] A flask conjured from thin air, was thrust into his shaking hands by Hermione. Harry lifted the silvery substance into it. […] When the flask was full to the brim, and Snape looked as though there was no blood left in him, his grip on Harry’s robes slackened.

“Look…at…me…” he whispered.

The green eyes found the black, but after a second, something in the depths of the dark pair seemed to vanish, leaving them fixed, blank, and empty. The hand holding Harry thudded to the floor, and Snape moved no more.