New button on the Cutting Assistant stage, just above the index-ring toggle: Loupe View. It opens a small panel with a switch and a speed slider.
Turn it on and facets stop popping into place. The stone rotates to face you, then the facet cuts in, fast at first, slowing as it nears the meet, the way it goes on a real lap. Blue marks where the stone contacts the lap edge; the cut turns yellow as it finishes.
Use Next Facet for one cut, or Auto Cut to watch the whole stone come out of the rough. Pause stops mid-facet and play picks up at that depth. The slider starts at half speed, about three seconds a facet.