It will hurt because of water's virtual incompressibility allied with high surface tension and being in an enclosed space means it can't easily be displaced by a falling object. Falling water, on the other hand, has much lower surface tension and is not in an enclosed space. If you're having trouble getting your head around it, I recommend you adopt an empirical approach:
Simply get someone to piss on you from the top of a skyscraper and make a note of the level of pain it causes you.
Repeat the experiment, but this time throw yourself gut first from the skyscraper into a vat of piss in the car park below, and then compare the results.
Let us know how you get on.
(, Fri 31 Oct 2008, 13:52, Reply)