... i used to use mephbot back in the day , i dont remember a moat trick... then again i was never the one actually killing him... you get him caught on something or something like that?... or something...?
All you do is tele to him, lure him down towards the moat inbetween the two landings (where he is and where you come down) stand far enough back so that you can see him just a little bit and fire away.