Zarek knew that he, at most, had half a minute. He didn't try to cut Eliz down because he knew that killing such an expert wouldn't be so easy. Plus, she had support.
That support wasn't just the archer. Using Eliz as a shield and stabbing her from the back would be enough to neutralize that threat. It wasn't the fatty either—it was clear he was mostly a defensive specialist, and considering the fact his greatest weakness had been speed, there was no way he could catch up to Zarek anyway.
The main problematic support was Urouge, who had fallen silent after having his location exposed. In fact, while Zarek was rushing toward the mountain range for cover and better terrain for him to take advantage of, it also happened to be the location of Urouge himself.
When Zarek triggered Unholy Beacon, he had actually ended up with not just one beacon returning, but four of them.
