You have to consider that it's not, what could be termed a 'normal' murder (well at least not in a British legal sense). Logic gets all twisted and nothing makes sense to the person in the middle of it all (the killer).
We also have to figure in that the son may have seen 'daddy' kill 'mommy' so because of this and despite the turmoil in his head, 'daddy' has to re-assure his kid and make things seem all right. Often the most common way for this to happen is that they kill the child too, almost as if in one manic rage, moving from one victim to another until its time for them to go as well.
That's not always the case though and for whatever reason the brain blocks out the initial act, maybe its tired or can't process the information so you get in effect in a lull. Then, maybe hours later the reality hits again "Woah, have I done what I think I have?" a little peek or whatever and bam, the original mood returns and the next phase begins. So, its not as much two separate attacks more one single passage with ebbs and flows.
Often, the final delay before the act of suicide is used to say sorry to loved ones (hence the placing of the bibles, maybe) and perhaps finally fully acknowledging the impact of what has occurred before it all gets too much once again.
I would have to say that I do find it disturbing (well not disturbing but I'm unable to verbalise it better) that he may well have been watching the PPV and sending messages to friends - I'm sure that they may give a picture of his state of mind or they may have come during a more rational moment.
Also, it seems that the WWE is trying to deflect and blame from the use of steroids - whether this is the right move or not will become clear with the release of the toxicity reports in a fortnight.