With Abby away at Becca's lab and Kane being held hostage, Clarke is naturally in the position of being the Skaikru leader to negotiate with Roan and his army.
Though Roan worked well alongside both Kane and Bellamy in the past, he's turned on both fairly quickly. There seems no doubt now that he'd execute both at a moment's notice.
Roan was committed to maintaining peace with Clarke and her people, at least until the discovery that Alpha Station was being fortified – and could only sustain 100 people.
Bryan: Are we ever gonna be done fighting? Miller: Hell yes. We're gonna build a house on a lake. We're gonna plant corn. And raise chickens. And grow old.
