It says in the Tips, Tricks and Notes section of Tip.It's Troll Romance guide: 'It is possible to safe spot Arrg. Range or melee him from the entrance and he should be trapped behind the wall near you.'

 

 

 

I tried maging him from the entrance, and he was able to come right up to me and melee me. He only had ONE HP left, and I died. He was hitting me faster than I could eat.

 

 

 

Said safespot DOES NOT EXIST. Unless I done it wrong. Where EXACTLY am I supposed to stand?

Jagex sometimes changes quests to remove safespots (like in DT). I would recommend checking guides on different sites to see if they are more up to date.