This is where I as a GM allow the player to throw 30000 shields. And then tell him his max damage does not manage to overcome it's DR. Since he doesn't get the magic bonus to shield damage. Then I immediately ask him one more question.
"How are you still breathing and living? You just went through the motions of throwing and unstrapping 30000 times in 0 seconds. No human body can take that. Even if you want to say it took more than 0 seconds you still have quite some explaining to do. In fact at 6 seconds you are still moving so fast that you have turned yourself into a fine red mist."
No amount of rules whoring will get you out of that and consequently, the pathfinder version of hell since they technically committed suicide. No deity likes followers that commit suicide unless evil. Even then they prefer you kill others in their name rather than yourself. Also you'd be in a form of hell anyways since your god is evil.
Also none of these rules cover retrieving a shield. Ready and searching through a bag are two separate things. Unless there is an item that allows you to pull items out as a free action. Either way he's still red mist. And explaining some things to the gods.
There are no rules for moving too fast in pathfinder. Try again.
Also, with a Clustered Shots and a blink-back belt, we can make attacks with our shield at all targets in 5 range increments for ifinite damage.