one thought: could the Shivans have actually managed to do the impossible? If gravity directly affects subspace, then would not have subspace collapsed one the super-nova came, thereby destroying the Shivans within?
They first launched a massive subspace pulse...and only then did Capella go Nova. Perhaps...the pulse, its a key to all this. I dont think it opened up any kind of node or layer into subspace - hell, I doubt it did anything like that. It appears more like....a signal, a beacon perhaps? Something that could send off a message accross subspace, perhaps outside the galaxy...maybe even the universe itself?
The sathanas then jumped out, but the few left behind would have been able to use the pulse, or what was left to trigger the explosion to make sure hte GTVA didn't follow the Sathani out, or find out what they were sending out either (now with ETAK, everything was compromised)....god knows where the sathani went though.........