As with most Cameron blockbusters, “The Way of Water” has a way of pulling you in, surrounding you with gorgeous, violent chaos and finishing with a quick rinse to get the remnants of its teeny-tiny plot out of your eyes by the final credits. Cameron fills three hours of screen time, with another 10 minutes or so for credits, with what feels like a single, extended, not-quite-”real,” not really animated but impressively sustained feat of visual gratification, if you don’t mind the cruelty-to-undersea-creatures parts. This time, in “The Way of Water,” James Cameron really does have a way with water.