Hidden Path question trouble

So i just killed the guardian of dreeg and got the Runestone of Dreeg, according to the note if I got to broken hills and into that collapsed tower with path blocked off by rubble behind the portal it’ll show me how to get past the rubble but nothing is happen and I can’t continue on.
Or am I in the wrong place in doesn’t look like I can get into that "undefined: area from anywhere else I’ve looked around and can’t find anything

Well, here is an album of Hidden Path location screenshots that you can use to cross-reference and make sure you’re in the right place: http://imgur.com/a/fmHHb

Oh so I was in the wrong area then thanks

But what’s in that area beyond that tower and how do you get there, map makes it look there’s something there…

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The real question is what the hell are the drop rates on the Sentinel’s recipes. Lost count killing him in ultimate…