I had a somewhat similar problem
It was at the beginning of my career in IT. I was working for a self-employed engineer who had set up a test bench for industrial pumps. I was in charge of creating the UI software (in Visual Basic - sorry) that would allow the users to start or stop the bench, and see what the test status was. Everything was supposed to be automatic.
It was an impressive machine, I must say. The pumps would arrive by overhead rail. Upon reaching the proper position, a pump would be lowered for pressure testing. Tubes would be brought into place and cover the proper points on the pump. Once that was done, water was made available and the pump was set to work to ensure proper functioning. When the test was over, the system would drain, tubes would be removed, and the pump went on its merry way.
My UI was supposed to show all the steps, which I am happy to say that, after testing it for every possible scenario, it did.
Once everything was ready, we went to do the live demo. Everything went fine until a few minutes before we were supposed to finished, when the test bench froze.
I looked at the engineer. He looked at me. We hadn't moved a muscle. What had happened ?
I'll spare you the description of the 90 minutes that followed, what it boils down to is that, somehow, the big red Emergency Stop button had been pressed on the side of the test bench.
When I got back home (late) that evening, I promised myself I was going to integrate the status of that button in my UI the next day.