A mob of rowdy teens stormed a Big Apple Scientology church Saturday afternoon, trashing the property and injuring a security guard amid a nation-wide rash of similar viral social media stunts, police and sources said. About 50 unruly youths barreled through a locked side door of the Church of Scientology of New York — which sits just off Times Square on West 46th Street — at around 4:24 p.m., damaging the premises while parishioners and visitors were attending a seminar, according to cops, police sources and the church. They also kicked a 30-year-old man believed to be a security guard, who was walloped in the leg and sustained minor injuries. The rampaging teens — whose act resembled part of the “speed running” trend that has seen similar acts at Scientology locations in Los Angeles — also hurled a racial slur at another staffer, the church said.…