"Haha I can't 'tell' you because the password can only be constructed from a specific series of hand gestures. Plot foiled!"
The attackers don't care if you can't verbally 'tell' them the password. With enough motivation, they will try anything to get it out of your head. A wench is just a tool to hasten that process, in certain scenarios. If you can't tell them, they will just hit you with a wrench until you tell them the exact way you use to reproduce what they need.
Edit: Thanks atatatat. Wrench, not wench.