Nam-gyu is causing Jun-hee to have a miscarriage in season 3
The more I think about it, the more likely it seems. Think about everything we know so far.
Nam-gyu is clearly misogynistic and violent towards women. He didn't want Se-mi on the team, he calls Jun-hee a "bitch", he specifically targets female contestants during light's out.
We know that MG Coin killed Thanos, the only person he cared about. Nam-gyu still has 7 pills left. Until he runs out, he's gonna be a gigantic threat.
This conversation shows he KNOWS Jun-hee is pregnant. He's the only player who figured out they were together on his own AND her pregnancy.
Jun-hee's actress called him "the scariest character". She mentioned "season 3 has an extremely brutal and cruel story." She mentioned having to film "an emotional season 3 scene".
Either Jun-hee will give birth and then die, leaving MG Coin to care for the child, or Nam-gyu's gonna stab/attack her, causing her to have a miscarriage.