Yes, if he was fueled by rage, after it dissipated, he wanted to get back to his normal life as quickly as possible. I don't think she's buried. I think she's in water, I thought that from the start because her bag wasn't with her, and they are searching water for a reason. If she's not then she's just somewhere natural in an equivalent location to the bag, tucked out of view in his eyes.
Lera213 posted about diatoms, I had been wondering what forensic evidence there could be to make them so focused on the water! So trace amount of algae could be found in his car or on Sierra's belongings? I wondered if her clothes didn't have some evidence of water because of Cardoza changing the wording of the urine question to "wet" and then no commenting. But they had the car by then. So maybe something in the car ... or maybe just because he said he went to Uvas??
Right now we are back to sleuthing LE's statements and actions because it is very likely they have a lot lot more. I agree we have no right to be privvy to it.
I have probably spent too much time on here, last night I dreamt my friend was old school mates with Casey Anthony and I was trying to get her to see the error of her ways allowing her to stay there with her four children, and the CA could smother one in the night without her even hearing!!