Boston - A man shot a doctor inside a leading Boston hospital on Tuesday, critically wounding the physician before killing himself.Authorities said Stephen Pasceri, 55, entered Brigham and Women's Hospital — which is affiliated with Harvard Medical School — sometime before 11:00 and specifically requested the doctor, who police declined to name because he is a victim.Pasceri, of Millbury, shot the doctor twice just outside an examination room on the second floor of the Carl J and Ruth Shapiro Cardiovascular Centre; he then turned the gun on himself, police said.Boston Police Commissioner William Evans said officers conducting a room-by-room search found the gunman dead in an exam room with the weapon. The doctor, meanwhile, suffered life-threatening injuries.The hospital said the doctor was in surgery as of Tuesday evening. It declined to release his name, at the request of his family.Police said Pasceri wasn't a patient of the doctor's and they didn't specify a motive for the shootings."Active shooter""We're in the process of talking to witnesses, but it's leading us to believe there was something in the past that upset this guy, that made him go in and look for this particular doctor," Evans said earlier in the day.Police and hospital officials commended the fast response by police and hospital staff, who they said had been trained to respond to an "active shooter" situation.Evans said police were on the scene within seconds after getting the first calls of shots fired and had the area secured within 15 minutes.Betsy Nabel, the hospital's president, said Brigham and Women's will evaluate its safety protocols. She said there have been no discussions about installing metal detectors, which none of the city's hospitals have.Tuesday's shooting prompted a temporary lockdown at the Shapiro centre. Hospital staff were asked to remain in place and the building did not accept new patients.