Your thoughts on what he meant with this...

That was fascinating. Many people talk to themselves, processing out loud (I'm one of them), so that isn't unusual. For instance, I do it when I am concentrating on fixing something and need to talk myself through possible next steps. All one 'conversation' while I scrape my knuckles and get frustrated.:-)

But what you picked up on, the multiple trains of thought, seems quite unusual. I am seeing one train of thought 1) talking to himself as if he were another person; 2) his 'reply' when he has to explain himself to another (repeating the question back to the questioner is a way to buy time, appearing to be an attempt at clarification but really just an extra split second). 3) what he imagines the other person will say when he 'replies'. So I catch three trains of thought...

1) "there it is. You're caught.
2) You're right of course. But you can't imagine!
3) Arrest him.
2) I don't know what's in the house.
1) Oh, I want this. What a disaster. He was right, I was wrong. And the burping.
2) I'm having difficulty with the question. What did I do?
1) Killed them all, of course.

The 'but you can't imagine!' line is something narcissists (all psychopaths/sociopaths are narcissists, but not all narcissists are psycho/socios) do when they are trying to explain the inexplicable. Somehow it is YOU that 'can't imagine' or 'doesn't understand' what it is like to be in their shoes. Because they are special in their entitlement, more deserving of respect and gratification than the rest of us and not constrained by the rules of normal civilized behavior that decent people abide by. So the 'but you can't imagine' is how the conversation in his head continues when he has to explain to another.

btw, like any narcissist, Durst used that 'special' attitude in his crazy explanations like why he shaved his eyebrows, why he stole a sandwich when he had $550 in his wallet and $37,000 in his trunk, why he wanted to delay the last interview to 'go on vacation to Barcelona', how he happened to fly in-and-out of N. Cal the same weekend Susan Brooks was murdered ("California is a big place!" smirk),etc. When asked for a reason he provides one in a reasonable tone, and people just let it go. No matter how crazy or unreasonable the explanation, there is no way for the other party to demand anything more.

I can try to hypothesize. I talk to myself and debate and argue with myself like that all the time. To an observer, I may sound fragmented like this not because my thoughts are fragmented, but because I think way faster than I talk, and I jump from one train of thoughts to another very quickly. So there might be 20 sentences between fragments of words out of my mouth - and they come out because they are a little more emotional thoughts. And they might come from different trains of thoughts.

I'm not schizo, but I have an anxiety disorder from trauma.

You know you have an inner parent in you that says things like, "there, you *beep* up again!" Then you have an inner child voice that says, "but it wasn't my fault!" and one voice might be stronger than the other.

One thing is clear, he was panicking. thoughts were probably racing through his mind. He was probably trying to think about what will happen next, regretting what he's done. etc, and these thoughts come out of his mouth when they are significant and emotional to him.

So his inner critic might say, "there it is. you got caught!" which is reaction to this interview blaming himself for *beep* up.

"what a disaster" clearly is assessment of the situation. Then he probably remembered what his lawyer told him, i.e. don't do this interview. So he says, "He was right. I was wrong."

He probably started to dread about what comes next.
Now he might be reviewing this interview, and started to imagine how bad the film will make him look. "The blurping" was a really bad performance, he blames himself. "I'm having difficulties with these questions" describes how the audience of this clip will observe. He's beating himself for acting so guilty.

He might try to comfort himself, saying, he will be OK. He's been in bigger trouble before. But the panic part of him argues, "but you can't imagine" what sort of sensationalism and public reaction is going to come.

"Oh, I want that" is a fragment that might have gone diabolical when he saw something, like that picture he said he wanted to keep. Could be any other thoughts, of course, like, I don't know, destroying that tape.

He might be starting to think about what to tell his lawyer. and one of the things he conjured up was, "I don't know what's in the house."

He would be thinking, what comes next? What happens after people see this film?
People are going to look at this video clip and say, "arrest him!"
Then he wonders, "what the hell did I do to myself?"
Then he thinks, "they are going to believe I killed them all, of course."

If I was his lawyer, I'd easily dismiss these. I'm not a lawyer, though.