FORCE /PAIN COMPLIANCE CURVE
When we are required to force compliance, pain or discomfort is a tool we can use. However, when using force or pain, we need to be mindful that too little or too much can be ineffective or even contrary to acheiving our goals.
As seen in the chart below, most individuals will struggle until the discomfort reaches a certain point. The window in which the subject decides to comply is fairly limited. When that window is reached, the pressure can be relaxed a bit, or at least the discomfort level should not increase further.
Behaviorally, the subject is complying in the hope that the discomfort will either cease or not increase futher. If the discomfort increases, the subject will resume resisting and eventually go into a hysterical state where they will lose all ability to reason. That makes them more dangerous to you and themselves.