initnpctimer;
while(getmapusers("g_room2") > 1) {
monster "g_room2",42,369,"Zombie-2",1015,1;
sleep 10000;
}
Use that to replace this:
sleep 10000;
monster "g_room2",42,369,"Zombie-2",1015,1;
sleep 10000;
monster "g_room2",42,369,"Zombie-3",1015,1;
sleep 10000;
monster "g_room2",42,369,"Zombie-4",1015,1;
initnpctimer;