The really remarkable thing about the blue field entoptic phenomenon isn't that you can see the red blood cells moving, but that you don't see the blood vessels and blood in front of the retina all the time. This is the brain up to its old trick of “editing out” distracting information.
Interesting theory to explain seeing movement of “white spots”. The trouble is that capillary blood flow (where red blood cells do indeed line up single file) is not generally pulsatile, as it is on the arterial side of the circulatory system. The pulsatile flow in arteries is highly dampened as arteriole diameter decreases. If it is pulsatile in the capillaries in the retina, it would be an exception to the general rule, of which I am unaware. Maybe the phenomenon is not dependent on pulsatile flow as the speaker suggests. If it does depend on it, there may need to be an alternate explanation for the movement observed in this exercise…