The phase transition from liquid to gas absorbs all the thermal energy in the remaining liquid and causes its temperature to drop to freezing point. You are familiar with this effect if you have used a tank of compressed gas; the tank gets cold as you release the gas and you might see condensation on the tank up to the liquid level.
But then the remaining ice in the glass sublimates anyway.
If it were a vacuum the water would quickly boil away with any remaining turning to ice.
It wouldn’t freeze unless you drop the temperature as well.
The phase transition from liquid to gas absorbs all the thermal energy in the remaining liquid and causes its temperature to drop to freezing point. You are familiar with this effect if you have used a tank of compressed gas; the tank gets cold as you release the gas and you might see condensation on the tank up to the liquid level.
But then the remaining ice in the glass sublimates anyway.
Who are you who are so wise in the ways of science?