Two thoughts....
First, you might consider just making a big battle with some random ships on each side flagged as invulnerable. When you have time, you can restart the mission, but even if there's a long delay, while the explosions may cease, the battle will continue.
Second, I seem to recall that (presumably unauthorized) in-store video is one of about two things related to FreeSpace for which Interplay has sent out cease and desist letters. I'm not trying to put you off of the idea, but rather let you know that Interplay has a bug up its arse about this kind of thing, so there may be consequences.