Does George Romero die forever once you kill him?

I know you have to kill him with the scavenger (thats the most effective from what i hear) and that his light flickers down to red and once you kill him he goes back into the water. But does he stay dead for the rest of THAT game? or does he come back in a round or so. I also know you can kill him with any other gun it just takes a **** load of time and bullets. And the VR-11 only makes him go away for a short period of time. (From my experience)