The truth was, at the moment, Zain couldn't bring himself to kill humans just so he could survive. Letting people die and killing them himself was a distinction he had made in his head.
If people were to die in front of him, even though he could help, he would say to himself that it was meant to be, and they were meant to die.
It was somewhat a cruel and strange way to think. Zain knew this very well, but it was what he had to tell himself in this current situation. Which was why he was able to twist his views a little more to do what he needed.
The two men were startled for a second when they saw the red hooded figure, but they decided to ignore the person and continue to run forward, but that's when the zombie who had leapt through the air spread his hands and was ready to grab the human.