@Benjamin Humans are not camels and we cannot drink vast amounts of water in advance and store it (as awesome as that would be). Our kidneys are capable of handling 800-1000ml of water per hour (https://www.scientificamerican.com/article/strange-but-true-drinking-too-much-water-can-kill/ ) and drinking much more than that can even have quite serious consequences. So there's just no way to *not* be dehydrated on a sunny June day if you cannot drink for 18 hours.

And no you can't sleep in that 5 1/2 block, because you still have to actually eat - meaning you will get less than 5 hours sleep …