The Knell Rings for the Living

(Zombie story, no special powers, no System, not a do-gooder, slow-paced, hard-core apocalypse.) On a night just before the New Year, Li Minghao was working the night shift at the police station when he received an emergency call. When he arrived at the scene, he found the caller dead in a gruesome state and the assailant acting strangely. Eager to save lives, he was made the fall guy by his superior. The dead returned to life, and his colleague was killed. Who was secretly pulling the strings? While keeping watch at the hospital overnight, he encountered a nurse of unknown origin. Was it coincidence or a conspiracy? Then the zombies broke out, trapping him in a hospital room. What should he do now? (The pacing is rather slow at first, but that's all to explain how the story begins.)