PLAYA DEL CARMEN, Mexico — Gunfire broke out in a crowded beachfront nightclub throbbing with electronic music early Monday, causing five deaths and setting off a bloody stampede by screaming concertgoers at an international festival in this Caribbean resort. At least one person died in the crush to escape and some of the 15 people wounded or injured were hurt in the rush out, authorities said. Quintana Roo state Attorney General Miguel Angel Pech ruled out any terror attack.