I've found in my experience that one of the following happens when you go swimming in class 4 (or greater) whitewater.
1) You realize that you didn't want to be here, and that you are never coming back.
2) You realize that your near-brush with death has not dissuade your interrests in whitewater at all... and you are hopelessly addicted
3) You get stuck in an uncomfortable possition on a rock (or similar obstruction) and hopefully get rescued... then return to 1 or 2.
I've been swimming in class 4 whitewater a total of 3 times already... you guess which of the 3 happenned.
Also... It might just be that the picture was taken at the wrong time, but judging by the way the person in the rear-left (of the boat)is holding his paddle, looks like you had a lilly-dipper in your boat.