The Westchester grandmother who plunged into an open manhole in Midtown was heading to work for an overnight cleaning shift just before she died, according to friends of the family. Donike Gocaj, of Briarcliff Manor, New York, died of unimaginably painful injuries, the city’s medical examiner has revealed. Gocaj suffered burns that included inhalational thermal injuries, along with blunt force trauma to her torso — all of which caused her death, the examiner found.