A mindgame is any play that works by hiding your intention. The classic version happens at a solid wall: the killer breaks line of sight and the survivor has to commit to a direction without knowing which way the killer is actually going. Guess right and the loop continues, guess wrong and the chase ends.
Mindgames run in both directions. Survivors fake a vault, hesitate at a pallet, or double back around a rock; killers hide their approach angle, feint a break, or use their power to threaten two options at once.
Because a duel is played repeatedly on the same map, mindgames become layered: both players know the ground, so each is reading not just the tile but the other player's habits from earlier rounds.