It happened during Rock Fest in Barcelona while Twisted Sister were playing on the main stage, and on the other Europe roadies were preparing

the equipment for their band’s show… Dee Snider went nuts because he could hear the guitars’ sound coming from the other stage. Although he asked the technicians to resolve the issue, he didn’t waste time and went on the other stage and took care of business on his own. Watch the video…

https://www.youtube.com/watch?v=be6llJ0T-H0