I'm so glad that everything worked out for you!
One other thing to remember if it ever happens again, heat rises. The warmest part of your apartment will also be the highest. So if you have a book shelf or some other high *safe* place, put him up there. You can also wrap him in one of those thermal tote bags (like they have at some of the grocery stores) or you can keep him in a cooler. All of these will help to insulate his water and keep it warmer, longer.
Hopefully you'll never have to worry about it again, but just in case, I thought I'd add in those tidbits as well. :)