I haven't used one, but from what I have read here, the Topsy-Turvy's can make proper watering very difficult. You keep assuring us it had plenty of water, but
*it is a very small amount of soil for a tomato (I tried growing a tomato plant in a regular container on my deck, bigger than the T-T, ended up giving up because I could not keep it watered enough, it would have needed twice a day)
*instead of the plant shading the soil to help it conserve moisture, the soil is hung up in the sun and wind to dessicate
*on top of all this the soil and the plant appear to be directly in front of a white wall which would reflect all the heat back, baking them. It slowed me down a bit that you said it happened over night. That would argue against the too hot and dry theory since it should be cooler at night. But the wall would keep reflecting heat through the night, thus continuing to desiccate the plant and not giving it time to recover.