SAN JOSE, Calif. - Taptejdeep Singh died trying to save others from a gunman. Kirk Bertolet saw some of his coworkers take their last breaths.And friends, family and survivors were left to mourn after nine men died this week when a disgruntled coworker hauling a duffle bag full of guns and ammunition opened fire at a Northern California rail yard complex, apparently choosing his targets and sparing others.Samuel Cassidy, 57, turned the gun on himself Wednesday morning as sheriff’s deputies rushed in at the Santa Clara Valley Transportation Authority in San Jose.Investigators were still trying to determine Friday what might have set off Cassidy, who for years apparently held a grudge against the workplace he detested.The victims were Alex.