The shooter had a 7 round clip. He shot 5 rounds into the head of the guy who fired him from his job as a women's fashion accessories designer one year ago. They found the remaining two rounds still in the weapon after he was killed.
He then walked away from the scene of that murder and a witness alerted two police officers of the murder. The police officers followed him to the Empire State Building. He turned around to face them with a gun in his hand. Between the two officers, 16 shots were fired. According to reports, 7 hit the shooter. Each of the other 9 bullets hit bystanders (non-lethal). Some may have been ricochet's.
Again, this was in a "gun free" zone like most shootings where more than one person was shot. The difference here is you have two police officers that caused most of the damage. Of course, the media is trying to spin this as an active shooter situation, but really it's just a revenge hit. After all, the shooter only put his bullets in his target.