Let's play with the idea of perceived time.
At any moment in the present time there will be people who perceive time faster than others. Say there is a person in the "lead", perceiving time faster than everyone else. This person is the only one with free-will, while everyone else is determined. Say the person in the lead gets in a car accident and experiences a slowing of time in their perception. Then someone else will take the lead and be the only person with free will.
This could be happening constantly, where the person with free will might only have it for a second before someone else takes the lead. Essentially, the person with the fastest perceived time is in control of the speed of time itself.
I'm not saying this is true, but it was an interesting idea I had tonight.