It started on the lower floors since most undead were summoned in the submerged areas, but the undeads were advancing quickly. Consequently, everyone was trying to get the high ground to escape them.
Soon, their mission to end the Blood Temple turned into only survival. There is no reason to fight if both sides will die in the end, and every death at each side would be a problem since the need to kill everyone twice.
Edward and Ramses were fighting Adel and Kluster while the Oracle tried to get back control over the minds. Frustrated she was because all the control she thought to have, was slipping through her fingers and losing the best mages quickly.
"We can't continue this, he is using our fight to grow his own power. Stop fighting, if any of you dies here he will use your body to summon a high monstrosity as the ones he already controls." The Oracle said.