An autopsy Monday determined that the 24-year-old former Boston University School of Medicine student cut several major blood vessels, including the carotid artery, as he inflicted puncture wounds and lacerations on his neck, arms, wrists, and ankles, Conley reported. Lindsay M. Hayes, a specialist in prison suicide prevention whom the Patrick administration recently rehired to examine a surge in suicides at state prisons, said last night that a correction officer should bang on a cell door or yell into the cell if he or she spots an inmate completely under a blanket.