Bullit used to be a good boy. What made him bad was not the fact he never got promoted, he never cared. He only turned sour when they nerfed his taunt ability. And he took to alcohol, which Dr Kavan secretly made from some wild kiwis found north of the island. Bullit said to him, "Dad, give me something. Give my life a meaning, please. They nerfed me and made me drink those energy bottles. I may be immature, but I'm no kid".
It might be Kavan's pleasing nature, or he might have a secret affection for the muscled private, who knows. Anyway he ended up submissive to the request, only on the condition that Captain EverSpark should never know about this. "You can't trust her. ♥♥♥♥ she can even make a boom cannon turn and shoot its comrades. She's the master of betrayal, the lord of the dark arts". So Bullit made the solemn swear and Kavan gave him what he wanted.
Bullit knew why Dr Kavan and the Captain didn't live well together. In the beginning it was the doctor's yellow crystals who did everything, from wood chopping to dish washing and foot massage. But then they started to complain, often to EverSpark herself. "Why don't your critters ever do any chore?" EverSpark said it was because she respected them, they were meant to die in the battle like soldiers. "So who are we, slaves?" cried the crystals.
The Captain felt for them. She reported Dr Kavan to the Human Rights Assembly, which was set up by the six great tribes themselves. And the doctor was found guilty of modern slavery. He was cleared of an unfounded charge of pedophile though.