Yeah it looked like a VMC demonstration. In full scale multi-engine stuff, all the various minimum and maximum air speeds are labeled as "V" speeds. VMC is minimum single engine control speed. If you drop under that speed with only one engine putting out power, the aircraft will initially pull to the dead engine and you cannot override that asymmetric thrust with the control surfaces. As the problem progresses, the aircraft will roll into the dead engine and there isn't a damn thing you can do about it then unless you are way high.