No sorry. I was describing a way to read the xml from STDIN. If you want it using your $kwords file then use following version.

open SEARCH, "<$kwords" or die "can't open $kwords $!\n";
{
  local $/=undef; 
  $_ = <SEARCH>;

  my @arr = split /(<MS_.>)/;
  shift @arr; # 1st element stuff before <MS_1>, so shift away
  my %hash = @arr;
  print map {($_, $hash{$_})} grep { $hash{$_} =~ $word } keys %hash;
}
close SEARCH;
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