If the human has that much drag, it would make sense to put an aerodynamic canopy around them. Also, to protect their faces and mouths from pressure.

Also, if they put a keel and rudder underneath it, and allowed variable speed on each motor, they could allow balanced steering. Things boat and jet-ski makers figured out eons ago.

Lastly, there is a measurement bias. They measure their speed via film frames and distance. For that to work, the person has to be near the surface so the camera can see them. Anyone swimming or scuba-diving knows the moment you break surface tension you’ve slowed down. They need a way to measure speed that keeps the device and swimmer under water. Like the shark.

Thanks for coming to my TED talk.

How fast is a shark? Odd reference. Do people usually have a feeling for that?