It was too sudden. They had no time to prepare. The Apocrypha were already completely organized and were ready for battle. However, the same could not be said of the Anunnaki and human soldiers.
The entire army had just gotten together. There were no plans, battle tactics, or even evasive countermeasures put in place. The lack of time they had to prepare was about to reveal the difference in preparation between them and the Apocrypha.
Arguably, the Anunnaki did have more time to prepare than the Apocrypha since tragedy had struck them before the Apocrypha. However, the reason for the lengthy amount of time it took to gather their forces was due to the absence of the King and Queen. It had been difficult to gather their forces because of this.
Unfortunately, no one had the favor of time on their side to even devise a quick plan. All they could do was fight back while giving orders based on hunches.