They don't actually fight here: even when Crystal has Dusaike take down the X-Men, it's more that he can't save everyone from a riot, and violence, without doing so. Crystal assures him that she'll take responsibility and Storm will understand, since the Inhumans had just tried to help save mutants from the Terrigent Mist cloud. (That is grammatically correct: Terrigen Mist is what it's called, and it's also a free ranging cloud at the moment. Before it was contained.)
Cyclops, who believes that the Inhumans lied about the Mist being safe, warns the world, a world that had been accepting of the Inhumans, making them mistrust Crystal, Medusa and the rest.
Medusa doesn't want to start a war, but knowing what she does? She knows one is likely to come, and perhaps inevitable. If it comes to the mutants or her people, she's choosing her people and wants to plan to win a war that she doesn't want to take part in at all.
The tension, the misunderstandings, the paranoia? I understand it. Each side has been used, manipulated, chased out of their homes. Someone has tried to kill both Inhumans and mutants at many points, and so I understand, and sympathize with both sides. Still, it's making me want to make things better because I feel so much for both sides - and I want to clear up the misunderstandings, try to help them both.
I know how this is going to end, though, and it's going to get a lot uglier before anything good can happen.