Make the most of the opportunity
Go expecting nothing to be given to you and fully expecting that you will make the most of the opportunity. You have a great advantage that you may have the ability to gather insights on those individuals you are meeting - unlike many career fairs. Prepare good questions, plan to engage each of them both personally and professionally and understand their line of business. You can research their organizations, open positions, and decide if you are going to use the time to learn more about their profession, gather professional advice, or attempt to make inroads as a potential candidate for the organization.