In high school I worked in a "blast freezer" in a meat packing facility. It was one of the larger units, maybe 10x10 feet, and we needed to get "suited up" prior to entering. It was typically -40F (C also) and would occasionally get considerably colder. We'd stack vacuum packed, cardboard boxed meat on the shelves.
This thing was billed as an alternative to "flash freezing" and had some really serious mechanical equipment driving it.
As you might expect, we were kids and we'd play with the cold. Putting anything we wanted frozen in there. One could spit and it would hit the floor frozen. In short order, the spit would be gone.
Very strangely, if someone passed gas in there, it greatly affected the odor and was unbearable. So, as you might expect, one employee made a game of this.
Because it had rapid air circulation, it could freeze skin in a few minutes. Our suits were really just heavy, fur lined arctic jackets with a balaclava and fur around the hood. Even so, 5 minutes was about all we could take. The Meat was frozen solid in no time.