Why did Jonas stood still when asher shot him with a pretend gun?

Jonas stood still when Asher shot him with a pretend gun because he was grappling with the concept of violence and its implications in their controlled society. The moment highlighted Jonas's growing awareness of the harsh realities and the stark differences between their seemingly innocent games and the deeper moral issues he began to understand. This pause also reflects his internal conflict and the awakening of his consciousness to the gravity of life and death.