Cao Pi has had enough pleasant interactions with the bartender spirits at the Invincible to just assume that the ruckus in the back is probably spirits tending the restaurant. Meaning, yeah, they should go and peek in to see if there's anything particular going on. He won't be afraid of them and won't even draw his blades, he just wants to see what all the noise is about and if they can flag someone's attention.

So he's down for going in with Ignis if nothing else.