While working safety on the outside of Corner 8 at Mosport during a Honda Michelin event on a rainy Saturday, one Civic lost it on entry, slid sideways, hit the wet grass and barrel-rolled 3 times before hitting the tirewall in front of me and coming to a stop wheels down. I scrambled over the tirewall with my fire bottle, ran to the driver's window and asked if he was OK. He responded in the affirmative but when I commented on the "nice rolls" he asked "What rolls?". I told him about his excursion as I was getting him out of the car but when he saw the roof wrapped around the rollcage, his knees buckled and he almost collapsed. He was checked out as physically fine but later in the paddock I saw his car on a flatbed trailer and noticed this upside-down sticker on his rear bumper: IF YOU CAN READ THIS, TURN ME OVER !