WARNING.. VIEW AT OWN RISK!!!
Before Tug-of-War, there was 80, which was reduced to 40.
Then the doctor was caught and killed: 39 left.
They paired up for the marble game: 19 pairs and #212 was left without a partner. Later we learned that #212 was simply taken back to the dorm.
19 pairs should result in 19 survivors, plus #212 = 20 total.
However, the score board, clearly says 17 left in the game, when they are done playing marbles.
What happened to those 3?