Rowan tells Olivia that as while he was Command, he gave the orders that make him responsible for the deaths of 183 people. However, Rowan admitted earlier this season that he gave Fitz the order to shoot down Flight 522 which killed 329 people. Therefore, Rowan is responsible for 512 deaths.
Olivia Pope is an employee of the Grant campaign and under no circumstances would be permitted to give an official briefing on behalf of the the government in the White House press room.
The B613 hit man manages to kill three people in a downtown D.C. street and casually wait for one of them to die slowly, all without being discovered.