Sunday, February 16th, 2014 5:09 PM   His shift had wrapped a while ago, but Eric LaCroix was staying on at the Black Petal, playing amateur electrician.    This was far from his usual purview, but it had officially gotten to the point where something had to be done. Most of the work day had been pretty good - regular flow of customers, good sales on coffee and pastries, and a musical sampler of some of the local acts playing over the speakers. Then, in the last hour, the audio had started