Megosztott hang

I stayed late after school—but I wasn’t alone anymore. The hallway lights flickered as I packed my bag. Everyone had gone home. Silence filled the building. Then I heard a chair scrape behind me. I froze. Slowly, I turned. All the desks were empty. Except one. A chair in the back corner was slightly pulled out, like someone had just stood up. I grabbed my bag and rushed to the door. Locked. I hadn’t locked it. My breath got faster. I turned back— Now every chair was pulled out