exactly the thought that occured to me earlier today.
But I think just a more straightforward method of abandoning a boss battle would do the job as well. This way, the surprise-aspect is still there (“oh look, a toaster”- /BOSS BATTLE -“OHH”), but you realize that there is the option of cancelling it and actually preparing, without having to figure out how to do it via other means (ie going to character select, switching channels etc.)
The other issue is partymembers being thrown into it who might be doing something else and are dragged into that one for the 20th time or something xDD But not sure if that really needs a fix, as it’s usually convenient to have the party warped to the event.