Power Steering Failed problems of the 2008 Mercedes Benz GL320

I was making left hand turn, suddenly the power steering assist failed and it was impossible to steer the vehicle to bring it to safety. This happened just prior to us entering the freeway. If we were to enter the freeway and this failure would occur on the freeway, we would end up in a crash. We contacted mercedes. They sent a tow truck and the vehicle was towed to beverly hills mercedes. We contacted mercedes USA to inform them of the incident. Their customer service called us back and stated that even though the power steering failed we should had been able to maneuver the car to safety ( which we were not able to do). Mb representative did not give us any assurances that the underlying problem of the vehicle being unsafe in case of power steering failure will or can be addressed since this was the way the vehicle was designed. We have 4 little kids and we feel it is extremely dangerous to drive this type of the vehicle with this steering design defect. There are thousands of mercedes GLS on a road.