She should distract him with a one on one brawl provoking BlackBolt to use his sonic power on her. Then have Alison pop out of no where and absorb all his power and lazer his limbs off.
To finish it off Emma should flood his head with nothing but memories of the death and pain suffered by all the mutants with this Terrigen Mist he launched. Death is too quick and easy for a mass murderer like himself.
Then her and Dazzler should continue to be badasses and just take down everyone in the Royal Family. Except for Crystal and Lockjaw. Those are the only Inhuman characters people unanimously like.