More of a game-thing than a ship-thing.
When an enemy ship blows up, all of its missiles do as well and the level effectively ends instantly right then.
It would be more interesting if, when the enemy ship goes Kaboom, the missiles keep coming, but a proportion of them randomly lose lock as they fly (say, 2 missiles per second or so). This means that you still need to defend against the final broadsides, moving the game closer to "reality" and increasing the possibility of suffering a mutual kill.
Conversely, if you get blown up by the enemy, the same thing would apply to any missiles you've fired, thus allowing you to achieve a "Taking you with me".
It would make PvP battles even more intense!
Just a thought...