I assume the warning about ice baths is because bringing anyone's body temperature down that much is dangerous. Don't let the hatchling go in water you wouldn't go in, assuming your biology is at all close to human or animal, right?

How are the canals in the Water Sector? Other than that, I wonder if taking a vacation to the seashore might be best. The water is cooler than the air is right now, and the turtles should be able to swim.

[Granted, the job at the hospital means that Septimus might throw a fit if Zel asked for time off, unless he was carting overheated kedan with him.]