It will cool off.... eventually....
Water absorbs much more heat than air, this is why we use ice baths. If we look at thermal conductivity:
Air 0.0243 W/m K
Water 0.58 W/m K
Ice 2.18 W/m K
Where W= watts, or heat trasfer per unit time
m = meters, or thickness of material
K = kelvin, a measurment of temperature
With these values and Fourier's Law, you can show that pretty much water and ice will transfer much more heat from your hot wort than the cool air of your freezer.
Application: Stick with the ice bath or some other type of immersion/cfc chiller method