Brake Master Cylinder problems of the 2015 Kia Motor Sorento

Vehicle stopped engine running brake pedal goes to floorboard. Dealer states this happens and demonstrated 3 similar vehicles brake pedal goes to floor. My experience and training indicates this condition is unsafe and master or wheel cylinder or disk brake piston may be leaking. Another area can be master cylinder internally leaking or abs internally leaking. I called kia corporate customer service and after listening to my concern he said he has no technical support to address my concern and to go back to dealer. However, I had earlier gone to dealer for a brake inspection �brake pedal travels too low�. I was charged 70$ and told everything is fine! I feel I am chasing my tail here. Is there no standard that says peale pedal cannot go so low that gas pedal is also engaged if foot overlaps accelerator pedal? pretty scary if you push brake pedal and it creeps low enough that gas is applied and they are fighting! two months ago I was told that if gas and brake were observed by computer the default was to shut off engine to idle. Yes this was happening several times trying to get onto freeway. Hit gas engine dies if brake pedal touched when trying to merge onto traffic! now I can hit gas and brake at same time and they fight each other. Help!.