Shawn, if I were you, I'd just have your character go do something else. If you still think Mythica might come back, you can be polite and come up with an in-character reason to leave the conversation (maybe your character got distracted with something else in the room? He could apologize and go over to see).
If you want to bring in a new character, that's an option too, but if you're going to keep both characters in the bar, yeah, might want to make sure it's okay with those guys. Best way to talk to them is probably just this thread, actually
In either case, her ceasing to exist is no reason you have to put your RPing on hold. If you feel like someone's disappeared, you're more than welcome to bow out of the interaction.
Hehe... Katrina, are you intentionally using Ewa to sort of critique and deconstruct the Space Bar and stuff? Or is it just working out so perfectly because she comes from a world that specializes in reconstructing the world that dreams up the entire world from which she comes?