If he speaks it doesn't mean what he says is true.
It doesnt mean its false either. And there is a very big difference between torture to obtain a confession and one to obtain information.

I speculate if you beat a man long enough he would either become insensitive or he would say what the interrogator wants to hear
And how do you know what he wants to hear? These guys are proffesionals. They going to test you and see if your telling the truth.