Since the Dhampirs had only attacked from one direction, the Red vampires thought they might have an advantage. Therefore to contain the Dhampirs to one area, all the Red Vampires headed for the entrance from where the former had broken through and had begun the attack.
The vampires wanted to use the location to their advantage. And had decided that upon reaching the entrance, they would fire off their blood aura, use their beast weapons and everything at their disposal to attack the Dhampirs that were coming through.
However, the Dhampirs were able to push through, and even took down a large number of the Red vampires for a few reasons. For one, the Dhampirs had all attacked from one location because they had predicted how the Red vampires would act.
If they were all together, it actually gave a little boost to the Dhampirs being around so many vampires at once. Using this adrenaline rush, the Dhampirs could defeat the Red vampires easier than they usually would have.
