Zimmerman laughs in court at deadly force testimony

In his trial for the murder of slain teen Trayvon Martin on Wednesday, former neighborhood watchmen George Zimmerman found a moment of levity during testimony about when it was appropriate to use deadly force.

U.S. Army Capt. Alexis Francisco Carter Jr. told a Florida court that Zimmerman had been "one of the better students" in a Criminal Litigation course he taught that included the state's "stand your ground" self defense law.

Defense attorney Don West asked Carter to explain how the self defense claim worked in Florida.

"On the issue of injuries, though, when you talk about that with the class and your understanding of the law is that the focused is what's going on in the person's mind, not whether they have actually been injured," West argued. "It's the fear of the injury, is it not?"

"It's imminent injury," Carter explained. "Or imminent fear. So the fact alone that there isn't an injury doesn't necessarily mean that the person did not have a real apprehension of fear. The fact that there were injuries have a tendency to show or support that that person had a reasonable apprehension of fear."

"You don't have to wait until you're almost dead until you can defend yourself?" West asked.

"No, I would advise you probably don't do that," Carter replied.

That response prompted several seconds of laughter from the usually-emotionless Zimmerman before he was able to look downward to regain his composure.

Watch this video from Fox News, broadcast July 3, 2013.