Torvus Temple Super Missile Expansion Glitch

The first time you come here, you are thrown into a scripted battle. This is how it is supposed to happen: 2 pirates swoop in on one of their flying drop ships... they jump of and attack you. After you kill them, 2 aerotroopers show up. After them, 4 pirate troopers attack. After you kill the 4 troopers, the super missile expansion shows itself and you can proceed.

What happened to me was that one of the two original troopers didnt jump off the ship... and flew up into the sky with it, removing it from combat and letting the 2 aerotroopers spawn. I killed the 2 aero and the 4 other normals... but the battle music didn't stop, the doors didn't open, and the super missile didn't spawn. Instead of resorting to my previous save, I look around and up... I see the lone trooper shooting at me from waaay away above the arena... so far that his shots vanish from the distance before they even get inside of the arena. I moved around and pinpointed the location of him outside the top and fired about 30 missiles at him until he died and the super missile spawned.

I haven't been able to repeat this beyond that one time, but it was a little depressing just looking around for it.