After leaving some instructions, Nile and his two companions immediately went out to hunt.
Of course, when he said he wanted to collect some food, he didn't mean the one in the groceries. What he meant was that he would hunt some zombies, collect their dead virus and let Gray make them into food.
After becoming the 'system' the map function was brought back by Gray and it's more useful than the previous one.
Right now, at the corner of his eyes, he could see at least 4 red dots scattered around the ancient house.
According to Gray, the map function was just basically sensing the New Generation of Xalax race around them. As an Anti-Xalax, Gray was extremely sensitive to the energy that the Xalax race gives off.