Suggestion. Dereference one at a time as you enter the loop. The logic will be simpler, the syntax saner, and by avoiding nested hash lookups your code will be faster as well:

foreach my $key (sort keys %tophash) {
  my $value1 = $tophash{$key};

  foreach my $subkey (sort keys %$value1) {
    my $value2 = $value1->{$subkey};
    foreach my $val (sort @$value2 ) {
      print "$val\n";
    }
  }

}
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UPDATE
Oops, forgot to do the second hash lookup. Fixed.