The battle between the Thanatos and the enemy ships had taken place at the edge of the planetary system, and when Eneas departed in his Phoenix, he could not risk being out of range of the ship's communications. There was also the portal that generated interference; they did not cut off communications, but to guarantee its stability, the signal power had to be very high, truly reducing the effective range.
Going out in force on his ship would have been very risky if we were not talking about a navy pilot who had already lived through a war on a fighter; going into combat in a mecha, although dangerous, would not be something they could blame him for.
The approach maneuver to the atmosphere was followed by the rest of Commander Antis's fast ships. All the ships in a pyramid formation began their descent. In those minutes Eneas contemplated the combat that was taking place on the surface.