> He also explicitly mentions he uses the ratchet by turning only the axle and keeping the handle steady in his hand for a lot of the screws.

This is shown in action at this point in the video:

https://www.youtube.com/watch?v=2K5Gqp1cEcM&t=606s

In many ways, this mimics the function of a jewelers screwdriver:

https://www.victornet.com/milpixpics/1315_GEN-SPC-100.jpg