Instinct.
Instinct was driving the two long-time friends now, and it was an instinct for self-preservation.
"I have a right…to walk away from you, House."
James Wilson's instinct was for flight. If he couldn't handle a situation he ran away from it. It had been a long time, however, since he had been unable to handle a situation. Being friends with House had taught him to handle pretty much anything. So after all he had seen and been through he didn't think he'd ever have to run away again. It was a mark of how deeply he had been cut, therefore, that he was determined to leave Princeton-Plainsborough Teaching Hospital.
"You're really milking this bereavement thing, aren't you?"
Gregory House's instinct was for fight. He always knew that if he fought hard enough he would always win as long as he knew he was right. The problem was, being right wasn't always enough. He had learned the art of the fight, but most of the time his fight would simply push people away. That was fine with him, however, he didn't need other people. Except, of course, for the one exception.
Both House and Wilson had instincts which normally served them extremely well. As doctors they had both been trained to listen to those instincts and trust them.
When it came their friendship, however, their instincts were dead wrong. Because in trying to protect themselves, the two were being pulled farther and farther apart from each other. And that, of course, was the last place either one belonged.