The emperor wasn't senile. Besides the torpedo started a chain reaction, not unlike explosions when tanker trucks are parked next to each other. The torpedo probably struck something which exploded another big thing, etc. Of course it didn't look like that on screen, it was one big bang. In the ep I finale, there were more chain reaction explosions in the doughnut ship, but it snapped in half like a twig. Aw, artistic license.