Also, a fraction of a milligram of plasma, suddenly free to roam about the entire to toroid rather than confined to a small part of it would lose temperature ra

Also, a fraction of a milligram of plasma, suddenly free to roam about the entire to toroid rather than confined to a small part of it would lose temperature rapidly. But yeah, magnets throwing around chunks of each other, and chunks of radioactive shielding, would be an unpleasant thing.