Poloidal field coils in ITER (and really any nuclear MCF machine that will ever be made in the future) integrate dynamic control. They operate on the microseco

Poloidal field coils in ITER (and really any nuclear MCF machine that will ever be made in the future) integrate dynamic control. They operate on the microsecond timescale, which is expected to be sufficient for expected instabilities. You'd never move a vessel that fast. It's my understanding that instabilities aren't heavily affected by the vacuum wall's location anyway.