Karcher rotary nozzle - Inventive Minds NEO needs

When I drive I don’t listen to the radio, instead I occupy myself with trying to think through how things work, or could work.

There are many forces acting in the nozzle - what kind of mind can "feel" the physics and design the parts of this tool so that each part works - high speed rotation, high pressures (1500psi) without coming into issues with other parts of the tool?  

Tip:  After several hundred hours of use the rotary tip stopped rotating.   If shock was applied, it would rotate for a few seconds, and then stop.  Long story short, my experience has been that if you take the nozzle apart, clean out any contamination which has entered any of its orfices, and apply axle grease liberallly, the nozzle will go back into full operation.  

This nozzle cleans about a 100xs better than a static, non rotating pressure washer nozzle. 

Explain why (on your next long drive)