Yes the towel can be the essential part of the technique, but I think you experienced something similar. The wet towel puts pressure on the face (the same psychology as a hood) and the dripping water makes it difficult (though not impossible) to breathe and talk. The brain thinks the body is drowning and causes a full on freak out.

I have seen some really tough (including military) guys and this breaks them pretty quickly.
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I've broken all my toys. Would you like to be broken?