If you look at the pictures it seems like the cooling unit and the power supply itself are in two separate housings. They state that both the power supply and the cooler are supreme quality (justifying the price...). And I agree - If water were to leak into the PSU itself, it would be a potentially lethal situation (literally!!): the PSU is 220 volts, not 5 or 12, and all of your components would probably be toast immediately, including your drives. Other electrical installations might also be at risk (especially if connected to the same wall outlet or fuse group of your home's main power board).
For sure it would be loud, violent and fast (a heroic way to go for your trusted PC, some would argue). And u better not touch that case when it happens...
...I might buy one... ;-)
B.
EDIT: Oh yeah, and by the way: "the supply is protected against power and heat failure" (maybe my german translation is less than perfect, but I think you get the point)