Just a few questions about the Lore between saturday and the outside

So i was wondering why the dragon controlled by nico actually attacked the ship. I thought Nico had Clancy under control so why did he want to attack Clancy even though everything went according to plan for him? And the Second question: What i really want to know is why nico was actually betrayed? Do we know the reason for These questions? If so i'd love an answer.