Aside from Drannor and Erean, who were hidden inside the first mine, everyone else and Zaos were waiting for the assassins to pass by them. Once they do that, they will attack them from behind. They only had twenty soldiers on their side, and Zaos just noticed that the assassins numbered one hundred… that would be hard. Even a surprise back attack won't cause much damage, at least not fast enough. That was why Erean and Drannor would also attack them when they focused on Zaos and the other soldiers.
Since Zaos didn't recover all his mana even after all that time, he had to be careful about how he spends his mana. Enhancing his sword with so much wind magic in order to make electricity appear was out of the question. Even though he might be able to make the energy last longer just by delivering direct attacks, it wouldn't be enough. Besides, Zaos's arms and shoulders couldn't withstand how much all that magic bolstered his attack speed.
