Zombie Disposal Crew

What if, you were in the middle of the desert, with a pistol. Your pistol contains one bullet, still unspent. You also hold a machete. You're surrounded by 18 zombies, who were disliked, and disrespected actors in mortal life. Do you, as a die-hard zombie killa, fight to the death, and enjoy cracking the cranium of said zombies, or do you take you're own life?

not considering provisions, what is the most easily defensible long term position you could be in?