9/4 Company Senior

I was sitting at my desk, looking at documents and taking notes. The light above my head turned off without a word. I turned it back on, and the senior said, "I need to measure ***, I thought you'd say something. Just turned off the light." Every time I turn on the light to take notes and leave my seat for a bit, they turn it off. This time, they did it right in front of me. I should have immediately retorted and shut them down. I wish I could react faster and express what I'm thinking. Every time I deal with these toxic people at work, I end up overthinking it myself. Even though they're the ones with the problem, I have to think about how I can handle them better so I don't get taken advantage of every time.