I wouldn't suggest cutting the white wire. It is the sensor. You can't unplug it either, it is soldered to the copper coils around the water container. I think your best bet is to unplug the two wires from thermostat and either solder them together or use the wirenut rated for high voltage to be safe and atleast 5A (is there such a thing?) so it would not overheat and melt. If you cut the sensor there is no going back.
And yes, like robthered said you are playing with high voltage and high current and some expensive equipment, I also hold no liability to whatever happens.