Thinking on possible motives. I think it's easier with KK. Seething jealousy of KB as AofA pointed out and possibly to prevent PF from revealing some damning secret she has and is holding over her head. She felt compelled to assist him. I won't speculate on the rumours here about why KK got a divorce. But, it's not beyond the realm of possibility there was something that tied her tight with PF and she was seething when she learned about KB and baby K.
Much more complicated with PF. He's got two women on the go, one his baby's mother and the other one he chats up and beds down when it suits him. Things weren't going well with KB, she realized he's no prince but actually a toad, but now there's a baby in the equation. Maybe KB found out about KK? There's a rodeo in September, just can't remember if that was in CO or ID. Was KK there? Remember, they own horses together. KB gives him an ultimatum? He knows if it ends, there's custody to be worked out. But, baby K is HIS and he's not going to give her up. Heck, PF may already have met someone online again. He thinks with the h@$d in his pants, not the one on his shoulders.
He felt trapped more than railroaded and his pitiful life reached critical mass in Sept. He wanted out of EVERYTHING so he could move on. So, I think his motives were custody (control) and his next hop in the sack. Pathetic.
Ironic thing for KK though, she thinks if KB's dead and they get away with this, she'd ride into the sunset with her cowboy. NADA going to happen. HAD they gotten away with this crime, he was riding into the sunset with someone else and what was she going to do? Tell everyone what he did and implicate herself?
I'm having a hard time determining who was more stupid.
ed: changed frog to toad. Frogs aren't as ugly.