rantanplane, you're mixing things up...
Your question was (as I understood it): "what if the pilot didn't see the cautions on the CAD because the CAD was dimmed?"
My answer is: "when a caution appears on the CAD, you also get the "MASTER CAUTION" illuminated. This is not part of the CAD display, hence it won't be dimmed when you dim the CAD.
This has nothing to do with the red warnings and/or the associated 10' endurance.
And there is no such thing as a "red master caution". There are warnings, there are cautions, and there is a MASTER CAUTION light. The latter illuminate for a (red) warning or for an (amber) caution.