Duo, a two-factor authentication system, will be employed at William & Mary to bring an extra layer of security to sensitive accounts.

This leads me to believe the solution is a simple case of passing a value in the URL, as admin is a valid username on the system (confirmed on the log in page) I originally tried appending ?user ...

Duo is William & Mary's two-factor authentication service. It provides an additional level of security to prevent unauthorized access to a variety of systems. Two-factor authentication helps protect ...