Hal transformed into his massive draconic form mid-way to Amador who was in his gigantic chaotic form and he struck the Emperor with his massive claws and caused him to stumble backward.
Amador had a protection of Chaotic energy and while that protected him from the infinitely sharp might of Hal's claws, it did not help him against the force of the blow.
Hal wasted no time turning around and slamming his opponent with his tail and it was at that point that Amador conjured a massive sword of chaotic energy to stab Hal with.
The Emperor was out of his wide arm spread posture but that did not cause the crack to close because he remained a conduit regardless of the position his body was in.
The sword swing by Amador was so fast that Hal apparently had no hope of moving out of the way in time but also had not actually wanted to move out of the way.