In my mind, if someone called me to come clean up a murder scene, I would be terrified they would then kill me as I'm now a witness! 911 would be my next action!
There's too much about this 'story' that doesn't make sense. And as Judge Judy says, if it doesn't make sense, it's a lie. I believe lots of what was told by KK is a lie, and the only way LE would know is if PK speaks! But, in PK speaking, he's going in implicate himself. Thus KK feels secure in saying what she wants, believing PK is NOT going to implicate himself by pointing out the lies.
I think both PK and KK are criminals and need to be in prison for the rest of their lives! What I'm not certain about is the role each actually performed in this planning of the murder, the murder, and destroying the evidence afterwards.
Maybe KK is a type of nurse that carries drugs...whether legally or not, and had Adderall or some stimulant to stay awake so long without sleep. If it was adrenaline only, it would have wore off quickly. I don't know how the majority of people's bodies respond to an adrenaline rush, yet I don't believe it would last days.