This story touches on why I'm not fond of multiversal storytelling: there's no real stakes. This being could have just thrown them into another reality, annihilated them, etc., and there would still be limitless universes. In fact, given what's happen in other storylines, the annihilation of entire universes isn't uncommon, with Dr. Doom doing so to one where he was a good guy because his alternate self was...too blunt in his assessment of the villain we all know and love.