ISEG generally represents retail orders, however I guess that could be a retail trader executing a short trade. Either way, I think just natural profit taking, to be expected and presents opportunities to add or take a new position here. Know what you hold and next week won't be so stressful for some.
My post is only my opinion, I recommend you always do your own DD! I am not a licensed broker or a professional by any means, so take what I say as entertainment value at best.