The Loop by Ben Oliver
Imprisoned in the Loop for a crime he didn't commit, sixteen-year-old Luka Kane can stay his impending execution if he agrees to scientific experimentation that will benefit the elite Altereds. Luka and his fellow inmates hear of unrest on the outside and after all the guards mysteriously disappear, they decide to plan an escape. But what they discover outside the prison may be worse than staying in the Loop.
Review from School Library Journal Starred:
Incredibly well written and briskly paced, this book will engage and enthrall even the most reluctant of readers with sophisticated dystopian world-building and events. On his 16th birthday, Luka Kane celebrates, (if it can be called that), inside the Loop, a prison where everyone serves a death sentence regardless of their age or background. Sentences can be postponed if an inmate agrees to subject themselves to scientific experimentation that is ostensibly benefiting those on the outside. Soon, however, rumors of a war outside the prison begin circulating among the inmates. Inexplicably, the government turns the rain off, and in a somewhat peculiar twist, the guards inside the prison vanish. Even more disturbing are the rumors of a virus ravaging the outside population, one that turns normal people into violent killers. As he tries to escape the Loop, Luka is faced with very real dangers within and outside the walls. This gripping tale moves right along, pulling readers into the world of the Loop. Luka is a realistic teenager being pushed to the edge; the faint-hearted may find themselves wishing for an escape, but will keep turning pages.