Well you already posted an effective way of healing people with a PK tag yourself. Although you might be able to create a temporary place with higher AP for PKers with the following script (Not tested and ertainly not sure if it works):
NPC Code:
if (playerenters||timeout) {
for (this.i=0;this.i<playerscount;this.i++) {
if (players[this.i].ap<=40) {
players[this.i].ap=41;
}
}
timeout=0.05;
}
But as I said I have no idea if it will work online.