Sal was actually having a good day, yes the Apocalypse had started, yes he was probably already dead, and yes he was alone. But above all, he was having fun, a lot of it.
On the day of the outbreak he had been going around the campsite as usual, begging for food and water an such, playing his ukulele in hopes of money, and then he found out that almost everyone had died. They were all sickly freaks and he was going to become one too! But did he care? Not at all, for now he had decided on survival. And so that was what he was accomplishing! Until he heard the voices, until he heard the slaughter of dead men walking, and then he quickly decided on joining what he hoped was a group. That could have been the best, or the worst decision of his life.
Sal was walking between buildings, staying in the cover of the trees as he watched taller, stronger people do the killing for him. He would make it look as if he just stumbled upon them, then they wouldn't think he was a weak link. As he watched carcasses fall to the ground, a ground now covered in blood, he found himself smiling. This was a good thing, his group would be full of dumb, strong people. And he would stay with them, until he had to leave, because in the end that group would fail. So he kept watching, safely, and he kept smiling, because he was happy. And he was having a good day.