It's true, current @Fr3sh is all chill, but post apocalypse Fr3sh will run out of herb sooner or later, causing his inner assassin to take control of his body. It's the only reason he smokes. He knows deep down he's a weapon of mass destruction, herb being the only thing that effectively helps to keep the assassin under control.
That said, i could run rings around Zach all day, Not to mention that His strenght and his huge body gonna be your ultimate downfall. He obsessed with lifting. All the food you two find ends up in Zachs stomach to provide energy for his daily training session. You gonna starve, and out of pure desperation you gonna turn into a vegan, eating all kinds of plants - with one of them being poisonous. You die and end up in Zachs stomach, right next to the baked beans you two stole together a while ago.
A week later Fr3sh, the Assassin, and I stop by to throw roses into your empty grave, Zach was kind enough to dig for you. We 3 gonna hang out together, having a drink or two, telling stories about good ol Kyle, while roasting your fingers on a wooden stick over the cozy camp fire.