My first paph lost its flower recently. The wilting process lasted several days. I noticed the sepals were looking a little transparent and within a few days it was drooping. The dorsal sepal really hung in there till the end. The day it collapsed was the day the flower fell off.
As a side note, I am drying it—and it looks like it could turn out pretty cool
(Pics of the dried flower further down the page, post #7)
Before:
After:
Below: Light passing through the wilting flower's transparent sepal.