The way I see it Viola has two options, and neither are good for the team dynamic. One, she attempts to blow Meera's brains out, which I really don't want, or two she lowers her gun and attempts to blow Meera's kneecap out, which would be slightly less bad but still not good... Or a third option... Someone stops her before things get messy in a bad way (so that things can get messy in a good way :3)