Sirens of Titan question: Kazak/Rumfoord split temp or per..

I'm confused by KV's comments about Kazak shifting before Rumfoord. The
exact quote is:
"The chain was empty.
An explosion on the Sun had separated man and dog. A Universe schemed in
mercy would have kept man and dog together.
The Universe inhabited by Winston Niles Rumfoord and his dog was not
schemed in mercy. Kazak had been sent ahead of his master on the great
mission to nowhere and nothing."

In a way, it makes it sound like Kazak and Winston are separated forever
(er, we'll ignore the whole "Everything that ever was always will be, and
everything that ever will be always was" and think of time as a linear
sequence where to an outside observer, one can discern a separation in
time between dog and master) ... however, the earlier comment is:

"Before my dog and I go crackling off through space like buggywhips in the
hands of a lunatic"

...which makes it sound like they're going together...it just turns out
that Kazak is getting a head start.

So what do we make of this? Should I be optimistic and take comfort in
the second quote, or pessimistic and take the first quote literally
(especially the last part)?

PS: I haven't read much Vonnegut yet, so this may be answered elsewhere in
a way (Kazak shows up in Galapagos from what I understand).

He reuses the name Kazak (in breakfast of champions, too), but I don't
think they should be seen as the same dog.

I haven't read Sirens of Titan in a little while, but from what I
remember, Rumfoord can't see the future beyond the point where he
fizzles. I think you can assume that he interprits this lack of ability
as meaning he will eventually fizzle out (fizzle isn't the best word,
but I'll keep using it!). Perhaps he just assumes as well that he and
the dog will be together. This winds up not being true.

I don't know, that's how I read it.