Asteria and Nyx were too far apart to combine.  Meanwhile another of Fury's subunits was shot and disabled, leaving Nyx alone, surrounded.  Fury's main unit, which had stayed behind with Orpheus and Mayura, was unable to clear a path for Nyx.  Sion didn't want Orpheus to fire on Nyx's position for fear of hitting Nyx, though it probably would have cleared out a good number of the harassing strikecraft.

Then, having taken care of some of the enemy ship's cannons, Legion swooped over to the swarm of strikecraft, sending his demon bits to shoot down the strikecraft with precision.  His distraction gave Nyx the opportunity it needed to make its way out of the cluster of enemy fighters.