There was a guy in my testing center whose computer test was turned off by the employee while they were walking around turning off computers. Despite the fact that he was sitting right there, half-way through his bio section, for some incomprehensible reason, the employee bent over and hit the off switch.
I was there when it happened, checking out, so I can verify that this did happen. He was so flustered that even when they got his test back on line 10 minutes later, with the correct time remaining restored, he couldn't finish. Probably should have tried anyway, but at a minimum, he'll be filing a complaint. Curious to know what happens.