Say what you will about the Arcade Fire’s particular brand of stadium-disco, but they’ve never been ones to avoid big themes. In “Afterlife,” taken from 2013’s Reflektor, frontman Win Butler appears to be equating the death of love with the death of the body, while Emily Kai Bock (director of Grimes’ “Oblivion”) seems to take Butler’s repeated cry of “where do we go?” more literally, positing that the answer is probably a stunning beach house or a beautifully lit warehouse.