They stayed behind or had some failures. Making sure the nova went off or that the other sathys could get out. Tho i dobut if it took all of them to start, that a handful couldent stop it...even temporarily.
Maby they are repairing the nearby subspace. The green wave looks like a subspace portal.
And the first time i did the last mission, i went for the node. Didnt get tehre in time. The other times i screwed the missino and stayed by the node, or went early... wouldent let me actualy get out. Had to redu till i died or tried to jump. And i love the Ares fighter. Its not stupid at all. It was my first pick in mulitplayer.