Today at PaleyFest, we learned something new. According to co-creator/EP/Showrunner Dave Erickson, “zombies can't swim. They can wade…. We've figured out the best ways to shoot water zombies. They don't drown. They keep floating back up." This was in references to one of the two exclusive clips shown the audience at the 33rd annual fan confab, one of which featured Nick Clark (Frank Dilane) under water as a zombie floats just above him. In Season 2 of The Walking…