Depends what he considers favor.
I don't think he values freedom and family like the rest of us do. Most of us most of the time value them and it helps us live within our moral and civil codes, staying on the good side of the law.
He operates in a different realm. The ivy reason he didn't kill anyone sooner isn't IMO because he didn't want to; he wasn't ready. He was still strategizing, assembling, salivating.
I think he feels thrill where we feel fear. He feels power where we'd feel shame.
Thumbs up, he was pleased with what he'd done. Horribly disordered, to put it mildly.
So for him to watch the surviving roommates testify -- to see their fear -- I daresay he would live for that. He's gross that way.
I don't think he'd care if it served his trial poorly. He's all in his head. It would feed
that beast.
As it was at his sentencing hearing, while at first blush, he appeared stoic and unmoved, IMO he actually reacted a lot. Microaggressions. Duper's delight. Subtle expressions but they were there. It continued to be all about him. "I respectfully decline." No shame, no horror at what he'd done, no hung head, no care even for his own family. Just nasty reactive Bryem.
It's worth noting too that, while WE weren't made aware of the witness lists until late in the game, they weren't late in the game for BK.
What changed IMO is the State calling for a psych evaluation. AT had skirted that, called him ASDL1 with OCD... without any actual proof -- opening the door.
ASD isn't a protected class for DP purposes but let's say AT could convince a juror that BK was a sympathetic soul -- or one we ought to have sympathy for -- because of his impairments (forget his stable childhood, forget his generous IQ, forget his general fitness, forget his advanced degrees, forget his lived infependence). Now flip that on its ear. Instead, present his psychopath. A cluster of personality disorders, a history of uncharged offenses, a history of creepitude, high scores in narcissism, low scores in empathy, and there goes juror sympathy. He's an unlikable chap who commit unthinkable crimes because he could. Because he wanted to.
He knows what he is. He didn't relish hearing it from KG's sister either.
IMO he pled guilty to block the very testing that would have underscored KG's sister's litany. He knows she's RIGHT and he hates it.
I think it's safe to say he didn't plead guilty to spare anyone, he didn't do it to be nice, he did it so he could control the narrative in his head.
He'll fill his time now objecting to minor irritants thst irritate him majorly, make demands on Mother and Father as he always have, and gloat at what he will continue to tell himself was a successful mission, regardless of what the evidence shows.
Obnoxious.
JMO
