As I read about how wonderfully INTACT the skeleton was, I wondered if that in itself does not strongly suggest that the Allosaurus did NOT die in a "cataclysmic flood."
Here's why: out here around Seattle, we have the the remains of a mudflow that occurred more than 5,000 years ago, caused by a minor euption of Mount Rainier. This mudflow was the consistency of CONCRETE, about 3/4 of a cubic mile in volume, and it flowed more than 60 miles from Mount Rainier to Puget Sound. The flowing mud stripped the bark off of broken trees. Had there been an allosaurus in the way I doubt that he would have remained intact, with most of his spine as carefully aligned as it was when he left his chiropractor's office that fateful morning.
I have also seen the basalt "melons" in Hagerman, Idaho left by the Bonneville flood 15,000 years ago.
Have you ever seen how rocks come out of a rock tumbler after the first stage of tumbling? No matter what shape they were in when they entered the tumbler, they come out quite well rounded off. That's what the basalt "melons" in Idaho look like, except that many of them are as large as a volkswagon beetle or the garage the beetle would sleep in! Imagine the force of a flood that would move twenty-ton boulders as if they were pebbles. It is unlikely that such an environment would leave much of anything caught in it INTACT.
POWDERED would be more likely.
In the case of this allosaurus, I think it may be more likely that he died where he stood as a result of a poisonous cloud of volcanic gas. Maybe the "air" suddenly became filled with sulfur dioxide or hydrogen sulfide (more poisonous than cyanide, by the way), or mabe the local air temperature spiked to 250 degrees. PLOP! One dead dinosaur, and any local scavengers would have died the same way, resulting in an undisturbed, intact fossil.
That's my story, and I'll stick to it until it is time to change.