Thanks Jaym.
It's definitely the Red section. The other sections on that "walk off" descent have broken boulders throughout the section, except a short section, between the start of the Final 400 ascent and a few yards to the west.
Here's a link to pictures and a thread from 2018 or 19, showing the route, and a picture with two abandoned ice axes where the hiker tried to cross the section and failed. That spot is the most treacherous place on Mt Whitney in May. That hiker had two ice axes, but no crampons. He should have descended via the Main Trail (his camp and gear were at Trail Camp), but must have mistakenly gone down the wrong side.