The MBE exam is mostly multiple choice elimination, and these multiple choices are filled with legal jargon and case law. GPT-4 picks the best predicted answer and can mimic reasons for the choice. This ability to mimic reasoning is good enough to receive a passing score on the MBE and many other exams.
And there is often certain common indicators to what answers exclude. So just excluding enough of these is already quite efficient.
Also the questions are unlikely to be very creative. I think it could be possible to train someone with good enough memory just based on existing tests.
