I would assume that it's venting into what is technically an exterior section, even though it isn't very exposed. Those are excellent turbines, by the way.
however... from an engineering and logistics perspective... there are four turbines with clockwise blades and four turbines with counter-clockwise blades. This means you have to manufacture, ship, and store twice as many blades, and keep track of them during the entire process, making logistics more complicated. It bothers me solely from an engineering perspective (not aesthetic in the slightest)