Can you just check whether the noun is the player before removing the noun from play? Something like this, in the appropriate rules:
If the noun is dead:
if the noun is the player:
say "[The actor attacks you with [the second noun], killing you.";
end the game in death;
otherwise:
remove the noun from play.
(I’ve typed this in, so you’ll have to take care of the indentation by hand.)
Your Check rule isn’t doing what you want because it doesn’t run until the next time that someone tries attacking the dead player. What happens is that when you try the action, the Check rules run, then the Carry Out rules (if the action hasn’t been stopped). So the Check rule won’t run again in the middle of the Carry Out rule. If you want to have something happen in the middle of the Carry Out rule, you have to do it there.