He should have stayed out of the water. Take another look right at the start of the clip. Pause it and magnify if you must, but look at how high the water is on his tires. There is about a foot of water pushing on them, and judging from the speed the water is moving (and the "bow wave" as it hits the tires) it is pushing hard. A person would be unable to walk through it. Their feet would be swept from underneath them and they would be getting washed downstream. If they snagged on anything they would likely be drowned because the water would be pushing them down as they tried to get up.
Do not underestimate the power of fast moving water.