Ummm... try rolling off the throttle. You are only in a vortex because the rotor system is developing thrust, trying to push air from above into airflow coming up from below.
Er, you mean lower collective, right? Roll off throttle and it's tatty bye, especially in such an unstable state. The engine has nothing to do with VRS or any stage of it: The flow you are inducing with pitch is opposing an inflow from below caused by an increasing rate of descent (which you also said). In auto there is little or no induced flow, so it can be a way out of the condition together with airspeed. Airspeed, however, is the only necessary condition to get out. And as coyote says, getting out of [even!] IVRS takes time and therefore height and as most IVRS situations are likely to develop late in a mismanaged approach to landing you are unlikely to have the height to get out. If you want to race your aircraft at the ground in those last few hundred feet, good luck!