Aha! Started William's route - think I figured out the problem. I responded to Sharpe's questions differently - changed it from saying that my favorite was due to "the most complex case" but because I related to them. Route's continuing now.
Still, seems a bit strange for the whole thing to fail because of that choice. I was mainly saying it because it seemed the most accurate, and because I thought it would appease Dr. Sharpe. I dunno if the game quitting was intentional, but it still seems like a bug.