Ouch... the worst part is its not a store bought machine...
I had to pass a YFZ450 that was engulfed in flames (only knew it was a YFZ cause I could see the frame, plastics were long melted) at Unadilla GNCC last year. I felt so bad for the guy, but the race goes on around ya. We all pass on the info at checkpoints but nobody carries an extinguisher on ATV's. It was sketchy because you had to pass by it pretty close to squeeze by, and man was it HOT.
My buddy also lost his 2dr jeep last year.. Veered off the road missing a deer, hit a telephone pole with a transformer on it and the hot oil ignited the jeep. THAT was a HOT fire, melted so much they couldnt identify the year from the frame for insurance, the ins guy had to call them to verify it was so destroyed. All aluminum in the engine gone, wheels gone, only thing left on a trio of snowboards was the carbon steel edges.. no boards, no aluminum bindings..
I put an extinguisher on the buggy though! No reason not to, there's plenty of room and plenty of reasons! I'm kinda surprised its not mandated to have one on for racing