When Zoey was a puppy we would limit his water intake some, but she would still get many water bowls throughout the day (with potty breaks after each one - she was lucky enough to have a stay-at-home-puppy-mommy for the first couple months she was with us, so I took her out every half hour). But when I didn't give her water and she was thirsty, she would wander down to the bathroom, climb into the tub, and lick the drain, since she associated it with water from her baths. Now when she's thirsty and the bowl is empty, she scratches at the mat underneath until I fill the bowl, and when I don't respond after a minute or two, she gets frustrated and pulls the mat out and runs around with it flailing. I don't really see it as freaking out though, I see it as her was of saying "hey, help me out I'm thirsty", much like I know that if she goes to stand at the front door it is her way of signaling that she needs a potty break.