During a fight scene, Idris Elba was a little too accurate and Chris Pine received a punch in the eye.
“Well, we were doing a fight scene,” said Elba, “and he got a bit cheeky, and I was just like pow! I didn’t mean to do it, but Chris was quite proud of it.”
“This cast goes all out, and I like to challenge them,” said Justin Lin. “We were shooting this third-act fight, and I kept pushing to get the right angle, to the point where Chris just got hit. Continuity-wise, it worked out. That black eye played so well in the rest of the movie.”
Source: The Hollywood Reporter