As you will see from this lesson – most of the time, this lock is not being done as correctly as it could be.
Even many Instructors of this technique do not understand about the control of the elbow that is required.
Now, for Prison Officers, that I have taught this to, there are other possibilities.
In the Eastern Bloc Countries I have taught, there are 2 Officers, PLUS the Prisoner is in handcuffs behind his back.
So, powering out is not an option. Plus the officers also use a Baton / long stick to gain extra leverage and force the prisoner to be bent over double as well.
This technique is for when you do not have those options and you have to do it all on your lonesome!