Something

on *:TEXT:!parting on:#:{ if ($address($nick,2) == $address($me,2)) {
  set %parting on }
}
on *:TEXT:!parting off:#:{ if ($address($nick,2) == $address($me,2)) {
  set %parting off }
}
on *:text:!part:#:{ if (((%parting == on) && ($nick isop $chan)) || ((%parting == on) && ($nick ishop $chan)) || ((%parting == on) && ($address($nick,2) == $address($me,2)))) {
  part $chan }
}