How does Kirito come back to life when he's fighting Heathcliff?


I was rewatching Sword Art Online and I notice that Heathcliff KILLS him and
yet, he is able to come back and finish off Heathcliff, how is this so?




Logically, there is a delay in between the death flag being detected and the
NerveGear frying the brain, which is explain by how a Revival Item ([Divine
Stone of Returning
Soul](http://swordartonline.wikia.com/wiki/Divine_Stone_of_Returning_Soul))
can be used within 10 seconds of a player's death.

However, as for how Kirito, whose HP was 0 but was still able to affect
Heathcliff, was explained by Kayaba Akihiko when he congratulated Kirito for
doing something that went beyond the system by using the power of the human
will. This concept is reasserted when Kayaba appears before Kirito in ALO and
reminds Kirito about how he acknowledged this.

It's more of an anomaly rather than any sort of plot hole. In essence, Kirito
shouldn't have been able to do anything when his HP reached 0, but he was
still determined to end the game because Asuna believed he would end the game
for her sake. That determination allowed him to transcend SAO's rules.




Logically, there is a delay in between the death flag being detected and the
NerveGear frying the brain, which is explain by how a Revival Item ([Divine
Stone of Returning
Soul](http://swordartonline.wikia.com/wiki/Divine_Stone_of_Returning_Soul))
can be used within 10 seconds of a player's death.

However, as for how Kirito, whose HP was 0 but was still able to affect
Heathcliff, was explained by Kayaba Akihiko when he congratulated Kirito for
doing something that went beyond the system by using the power of the human
will. This concept is reasserted when Kayaba appears before Kirito in ALO and
reminds Kirito about how he acknowledged this.

It's more of an anomaly rather than any sort of plot hole. In essence, Kirito
shouldn't have been able to do anything when his HP reached 0, but he was
still determined to end the game because Asuna believed he would end the game
for her sake. That determination allowed him to transcend SAO's rules.

