When the Wraith Hive ship breaks in half, the "front" portion of the ship falls "down" toward the planet. If the ship is circling the planet in orbit then there's no way that the ship would have fallen immediately. In fact, it would likely have completed at least half an orbit or so before its orbit began to decay.
The "rear" of the ship should collided with the former "front" because the front would lose a measure of its orbital speed.
Losing orbital speed makes the ship orbit lower. The front portion of the ship didn't nose-dive. It rotated to a nose down attitude, then, when it finally hit atmosphere, in half an orbit or so, it slowed even more until it was actually falling. It could not hit the rear part because differing orbital speeds means different orbital heights (above sea level).
Losing orbital speed makes the ship orbit lower. The front portion of the ship didn't nose-dive. It rotated to a nose down attitude, then, when it finally hit atmosphere, in half an orbit or so, it slowed even more until it was actually falling. It could not hit the rear part because differing orbital speeds means different orbital heights (above sea level).