Episode 78 - Backdoor Bingo Oddity

Jim Willing from the Spooky Pinball Podcast's EM Dungeon segment (spookypinball.com/podcast) emails with a question on an odd back door switch on a bingo.  I give him the wrong answer and he graciously provides the correct one.
To be fair, I was nowhere near a manual, schematic or bingo when he asked, but I tried!