The default symlinks for killall set it up as K90 in runlevels 0 and 6. But /etc/rc.d/rc will never run it, because it will only run K* scripts which have lockfiles in /var/lock/subsys, and killall obviously doesn't. The solution is to make killall S00 instead of K90 and change halt and reboot to S01.
will be fixed in next initscripts release (4.25 or so)