2nd May 2013, 10:20 AM
It seems I got things confused from your description. It wasn't the explosive medallion, but the freezing "ether" medallion you needed to open the door in Misery Mire.
"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question." ~ Charles Babbage (1791-1871)