The red dot in post #309 is the position of the snow cave.
Hi sissyjane,
I am not qualified to make the call here.
If what I am calling the belay station is left (east) of the snowcave, then it would seem they were traversing to Cooper Spur for a quicker and easier exit... which would also be in line with Nikko's inquiries at cascadeclimbers.com, (It was one of the routes he proposed as an exit), and suggests that they were reasonably on their mark when they commenced descent.
But another thing comes into play too, if they were under pressure:
I can guarantee that some of the known routes are bolted, IOW, have permanent bolts to clip to in opportune places...
They may have been trying for a bolted route for descent, as they could descend quickly, perhaps having to sacrifice a beener (carabiner) on every pitch, but that would be cheap for a quick descent...
They might also have been ascending to the summit, as that would get them quickly to the east/southeast side, lee of the storm, which would be coming in from West/Northwest (center/right).
Sorry, I could be all wet. One would best get an opinion from the local boys.
-Bruce