America is grappling with yet another mass shooting, this time at a hospital complex in Tulsa, Oklahoma. Four people were killed before the gunman took his own life. Among the dead was a surgeon who had been targeted by the shooter, a former patient. The doctor had been treating the 45-year-old shooter for persistent back pain. A second doctor, a receptionist and another patient were also slain in the attack. So far in 2022, more than 18,000 people have died from gun violence in the U.S.