Hope your experience is nothing like these two guys
Learning, to Fill in Knowledge Gaps
Consultants are teaching employees something that only needs to be learned once, and then improved upon in time. Consultancy is improving the baseline knowledge, familiarity and skill level of an entire organization, division, department, or team. Getting to that baseline knowledge may be a walk in the park for you. It may be very difficult. Your job is to get to the baseline.
Asking Many Questions
Consultants won't be able to fish everything out of you, so you need to ask them questions, and answer their questions as fully as possible.
There is a saying in the old testament, that says "When someone pulls your cloak, reveal yourself." Don't keep hiding; In fact, proactively reveal yourself. What are you dealing with? What problems do you face? Ask the consultant what their goals and objectives are, so you can frame your concerns into their expertise.
You are the expert at what you do. Your company brought consultants in to find out how well you do your job, yes; but they also have a significant investment in making you better.
You need to be willing to improve, but don't be afraid to tell them your pain points. Tell them how you are solving those pain points, and hopefully, usually they will offer better solutions.