South snares too. Chances are if they are just starting SoF, they won't have the dps to deal with north mobs getting to him, iirc that causes the nasty a/e.
Honestly, this and Wirlem aren't worth the effort. Work on BM 1. It's simple, Bm 2 is a bit harder but not too bad - make sure tanks turn on their aura effects so they can see the graphic that way they know when to move the mobs. Frankly, if you can do Octa, hit MB in the sf instance. Better loot and you're working on progression.