According to Mark, what's true about '''hits''?

Mark thinks its okay to "hit", as long as you've been hit first.

"Impulses to jump out of cars and hit people?" Cathy said dryly, and I realized she didn't think Mark was a hero for what he'd done. As a matter of fact, she didn't think too much of it.

"They hit us first," Mark said, sitting back in the seat. "A hit don't have to be physical. I couldn't hit them the way they hit us without hitting you, too."