Knox Boxes, along with other rapid entry systems are increasing in popularity, as they allow first responders such as police, fire, and paramedics to quickly gain access to a building in the event of an emergency without having to force entry. These devices rely on the security and key control provided by various locks to prevent unauthorized access to buildings. In this talk, I will focus on vulnerabilities of the widely used Knox Box and Medeco cam lock to key duplication attacks. I will demonstrate how a sufficiently skilled attacker could obtain a key that would grant them access to thousands of residential and commercial buildings throughout America, as well as show off new tools designed to streamline the process of duplicating physical keys using CAD and 3D printing. What could possibly go wrong when someone tries to backdoor an entire city?