It was during milling. I believe that Peter was watching the start boat, saw the orange smoke, and just took off without the vision to see where he was going. Unfortunately he ruined Steve and Stevens chance at the championship before the first race started.
I'm still shocked Peter did not get at least a 2 minute penalty for being on plane during milling. The rules say DQ, but like I said, I think the orange smoke may have started when I watch the video and compare it to the accident from the last time Boatfloater is seen in the vid.