There’s this thread that’s discussing the elimination of the feature that would alert when your ice bath moved into the “danger zone” for temperature:
No, you wouldn’t be putting your food into room temperature water and leaving it there for several hours - that’s certainly a recipe for getting sick! 
Using an ice bath is how you can have a delayed cook that you can kick off several hours later without having to be there to put the food in the bath. (ideally, you do some experiments/tests with your own ice bath, ratio of ice to water, etc, so you know what the cooling rates are as well as how long it will take the Anova PC to get it up to the desired cooking temperature - as you’ll still have a target time that you’ll want your food to be ready)