I thought I read somewhere that he did a bunch of fills for the ending and they picked the ones they liked the best.
Anyhoo, are we talking about the second fill? The triplets? I think that they are just your classic right-hand, left-hand, kick-foot, possibly with a bit of reverb? That's the way I always heard it.
The wild one on the fade-out is just single-stroke 5's on the snare and a bunch of 16th notes across the toms. Remember, Stew grew up with Billy Cobham, who is notorious for that kind of stuff. It's just a matter of getting the hands to pull it off (a little caffeine don't hurt once you hit your 40's
).
BTW, has anyone else ever noticed that Stewart has never, ever played a double-stroke roll?