BEGIN {
  a = "generated/AWK-21-003-a.txt"
  b = "generated/AWK-21-003-b.txt"
  printf "%s", "" > a; close(a)
  printf "%s", "" > b; close(b)
}
{ out = ($2 == "labA" ? a : b); print $1 >> out }
END {
  close(a); close(b)
  print "labA:"
  while ((getline line < a) > 0) print line
  close(a); print "other:"
  while ((getline line < b) > 0) print line
  close(b)
}