To make him confess what? Truth? Or lies? How can one know which it is they are telling? For under unendurable pain a man confesses anything that is required of him, true or false, and his evidence is worthless.
[Tucker is in the agony booth, groaning in pain.]
Archer: Who ordered you to sabotage the cloak?
Tucker: I didn't! [Writhes as he takes another jolt.] Reed, I'll kill you when I get out of this!
[Malcolm is at the controls and enjoying himself.]
Reed: I'd like to see you try.
Archer: I checked the records. Admiral Black recommended you for Chief Engineer. He insisted Forrest replace his own man with you. You're working for the Admiral, aren't you? What have you told him?
Tucker: Captain, you've got it all wrong. It wasn't me!
Archer: What have you told him?
Tucker: Please, Captain. I've always been loyal to you!
[Unconvinced, Archer heads for the door, and pauses to give an order before leaving.]
Archer: Break him!
— Star Trek: Enterprise, "In A Mirror, Darkly"