A Salem State University student accused of stabbing two people aboard a campus shuttle in September was ordered held Tuesday pending a dangerousness hearing, prosecutors said. At his arraignment Tuesday, Timothy Wells, 25, was ordered to undergo a 20-day mental health evaluation at Bridgewater State Hospital on assault charges in the alleged Sept. 25 attack, the Essex district attorney’s office said. Wells is accused of stabbing a female student on the shuttle and then stabbing the bus’s driver when he tried to intervene, school officials have said. Both victims suffered minor injuries, and Wells was arrested in upstate New York later that night, school officials said. Wells will return to court Nov. 8 for a dangerousness hearing.