While Reign and the others continued down the corridor after the battle against the assassins, Magokur and his forces had begun with their plan. As Magokur had told Reign and the others earlier, they only needed to pass through 3 areas of the base before getting to the chieftain, the first of those areas were the trap-filled room that served as the first line of defense and the long corridor where a large group of monsters could charge and fight.
They had successfully passed that area and would have to pick one of 5 paths that were presented at the end of the corridor, out of the 5, 3 were dead ends that were filled with many kinds of bobby traps and only 2 would lead them further.