The second part of the track ("Lurker") is about a submarine. I read on a fan site at one point that the fire mentioned in the song is not a projectile attack, but the reaction fire. Fire consumes oxygen and therefore depletes sailors' air supply faster. As for the "heart of stone", it has been suggested that it is the uranium core that powers a nuclear sub.
The second part of the track ("Lurker") is about a submarine. I read on a fan site at one point that the fire mentioned in the song is not a projectile attack, but the reaction fire. Fire consumes oxygen and therefore depletes sailors' air supply faster. As for the "heart of stone", it has been suggested that it is the uranium core that powers a nuclear sub.