Well, watching the video, it's actually pretty easy to see how it happened. He tried to play his second drive that had gone way right into the brush. Once he hit that ball, he lost the option of going back and reteeing. The brush was so thick that he was having trouble moving the ball more than five or ten yards at a time, and sometimes the ball went backwards, but he had no other options at that point. Unless he could have declared an unplayable, and somehow moved back on a direct line from the green to his ball where he could have found a spot that would have let him loft it out of there.
He did make a nice 6-footer for the 16.
He then went on to not card any more bogeys the rest of the day, moving on to play the back nine in 3-under 33. Pretty impressive, actually. And he was smiling when he was walking up the ninth hole.
Na to caddy: "How are we going to count all of those shots?"
Caddy: "I have no idea."
Na: "I can't keep track."
Caddy: "They've got it on tape, they're just going to have to go back and count it."
Good stuff.