This may be the craziest malfunction of an amusement ride I’ve ever heard of. The E-stop literally didn’t work and maintenance had to disconnect the power from the ride.
That’s literally what both the article and my post said they did. You don’t just unplug a ride like you can unplug a toaster.
You are over simplifying the complexity of this situation. Most rides aren’t even just a single breaker and many can be powered from different sources. This isn’t just going to the amusement park’s breaker panel and flip a single breaker per ride. Also keep in mind that on some rides once you were to cut power it could also render the brakes useless as well meaning the ride would have to coast to a stop. In addition to this the ride ops aren’t going to have the ability to do this so maintenance staff need to respond in order to perform such an operation. Ten minuets is incredibly fast in this situation.