What indicates that the threats' engagement is effectively stopped?

The indication that the threat’s engagement is effectively stopped is best represented by the situation where the target is immobilized. When a target is immobilized, it means that they are unable to engage in further hostile actions due to being rendered ineffective. This can result from injury, equipment failure, or any other means that prevents the target from moving or engaging in combat operations.

While other choices present situations that could imply a reduction in threat level, they do not definitively signal that the threat is completely neutralized. For instance, if the target has been killed, it is reasonable to assume that the threat engagement is stopped; however, this outcome can occasionally be contested if there are other threats present. A target taking cover may still pose a significant risk if they are able to re-engage when conditions change. Similarly, while the retreat of a target can indicate a decrease in immediate threat, it does not guarantee that the threat has ceased, as the target might regroup and return to engagement at a later time.

Thus, identifying the target as immobilized is the clearest and most conclusive indicator that the threat engagement has been effectively stopped.