I am happy to report that you can dashboard whenever both characters are knocked out. Hit the guide button and force quit game when both Yu and Kay are downed. If only one is downed, it is totally fine even if you pacify the last enemy without reviving them.
This unlocks after you complete the epilogue and are basically at the title screen. I was scared I missed it because or how late it showed up.
It auto saves whenever you get to another section so you aren't placed too far back.