Well, I finally had to resort to using a trainer to get through it. I have no idea why there aren't simple debug commands available to get around problems like this. Not every player wants to have to send a save to the developers just to continue playing the game.
You can also get by with setting the difficulty to Casual. The bugged attack is still
there, but the damage it does drops to the point you can survive it. The reset to
to Normal right afterward.