Once they all released their killing intent they also stopped holding back as each of them knew that this was the last clash that they would have before one of them left with the prize that they all desired. If they kept holding back then all of the injuries that they had suffered until now would have been for nothing.
The remaining beasts put aside all racial ties because all that mattered now was the Iris. It was common when Havok fought other blue core rankers that they were killed by the end of the battle. However, that was not the norm. Most blue cores could tell if they were going to lose and retreated before they were killed. After all they did not become a powerhouse by making rash decisions with their lives. There was always a chance for revenge later. Once you died that was it.
