Darius' increased Intelligence might not seem useful in this situation at first glance, but it subtly powered up all his spells. The chief of this was his Heal spell in terms of combat effectiveness against undead.
Now, he could one-shot any undead with less than 800 HP. Darius didn't hesitate like before, he simply selected targets with his mind to be struck by the Heal spell while using his two hands to wave his steel spear around frantically, swatting away any interlopers.
The good news was that Gunner hit his top speed finally, allowing Darius to see the end of the encirclement just 50 meters away. With his sharp eyes, he chose an undead at the forefront to hit with his Heal spell, disintegrating and scaring the others to dodge aside.
This had the beautiful effect of creating a small pathway in between the wall of undead. With Gunner's current speed, they crossed those 50 meters in just 1.3 seconds, freeing them from the dire situation they were in.