Yes -- absolutely possible.
Sounds like you want your Inspector to have the ability to see the hidden sections of a course (moodle/course:viewhiddensections), but not control it's visibility (moodle/course:sectionvisibility) - definitely two separate permissions.
Another consideration -- add a folder to your course that has all the answer keys in it -- and either hide the folder (so students don't see it), group the folder to a specific group (such as a Teacher's Only group), or remove the students role's capability to 'view' this specific Folder (at the activity level).