For a rear tire to cut loose like that he may have had an oil or water leak, I can't tell if the bike had a belly pan or not. His rear tire have over heated and gotten greasy, some tracks require a harder compound, for example Robling Road in Savanna Georgia, and Daytona soft compound tires are a huge NoNo there. Another factor could be, we're the tires cold? Or old? Or street compound? Also the guy in front of him who took the same line may have been leaking oil or water? There are several ways to try and save it when the rear slides out, one is stand up on the pegs, get your ass off the seat and let the bike come back in line under you. If you chop the throttle like this guy did expect a high side like he got, been there done that. I've also held the throttle open and the bike will just lay down and slide away, been there done that ( daytona exiting the chicane) I've also gently eased off a hair and lifted my butt off the seat and saved it. I've raced CCS for 20 years, had an AMA Pro license, won a few CCS championships, loved racing in the rain and I am a guest instructor for the Penguin Race School, I also teach cops how to ride a Police Bikes. So have a little experience to back my advice