In article et,
Matt Young wrote:
during descent through the clouds, or will the gyros keep spinning fast
enough long enough to make the vacuum pump irrelevant?

I question the wisdom of relying on an instrument that you already know to
have failed. You would need to know just how long you can stare at it
in a very stressful situation before you can no longer believe what it
tells you. I would think that immediately covering the instrument would
be your best course of action in this scenario.