Step Turn, I'm afraid that closing the throttle on a twist grip collective will only reduce the severity of the problem not cancel it. To kill the torque reaction you need to shut the engine (the torque provider) down entirely.
In a Helicopter without a twist grip you will most probably have to take a hand off the controls to shut the engine(s) down - hence, something for the co-pilot to do for you, if you are fortunate enough to have one that is !!