Wouldn't it be a smaller region? If the galaxy was peppered with
events which normally wiped out a sphere 1000 ly in size, and we
waited long enough that almost all the galaxy would have been
covered a few times, then there might be a few places which were
left uncovered. They would be little cracks among the bulk of the
galaxy which had experienced the explosions. So I think we would
expect to find ourselves within one of those thin areas just outside
the boundaries of several nearby explosions.
Hal