New York City’s subway system is the largest in the world, and its thousands of entrances and 800-plus miles of track make it vulnerable to attack. On April 30, a college student disguised as a track worker exposed just how vulnerable that system is. Police said a Pace University student dressed in a reflective vest, a backpack, hardhat and boots wandered for hours underground before being picked up by suspicious track workers. “In the backpack was found a can of sodium cyanide, five flares,” the NYPD Commissioner said. The student told investigators he wanted to commit suicide and didn’t want his body to be found, but a special team was called in to investigate the chemical being carried inside a gallon-sized paint can found in the student’s possession. “Sodium cyanide does not have an explosive quality or capability but is highly toxic,” the commissioner said. A security expert told CBS 2 HD, “We can go right now into any train station, walk down the platform, walk onto tracks and we’re in the tunnel and it’s gonna take a long time before anybody sees.” The expert, a former co-chair of the New York State Anti-Terrorism Task Force, said without a completely monitored transit system, it’s up to New Yorkers to be ever vigilant. “This is where the millions of riders that get on our trains every day, the workmen, everybody involved ... they see something, they report it and they take action. That’s about the best we can do,” he said.