I had a similar reaction, as though he'd expected the question and spent hours going over his response - a response he planned to be very presidential and one that would make each of his petty attempts at national defense seem to be much more than they were in fact. He planned to show a 14 year VRWC effort to discredit him and to highlight alleged failures in the present administration.
He'd planned all that but somehow piled too many potential responses into his bag and at some point lost cadence and began to simply dump them out, once he'd tripped, the anger was a response to finding himself floundering and turned into rage.
I suggest this because I've seen similar reactions, in MUCH lower doses, from myself and others when the presentation starts to go astray because you've got off by just a tad and feel that you've lost the handle.
It'd be interesting to review the tapes and see if there was some little stumble that set off the following tirade.
When he said that the newspaper's headlines are Bush'e fau -responsibility...
I think the "bones" comment is where he dissembled and lost it.