Patience, patience, patience. Clear some tar, inspect the room carefully to see if you made a mistake, and then go back to the checkpoint. The checkpoint is your friend.
Possible specifics:
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×I believe that I did the SE corner first, then the NW, then the last little trapdoor by the wraith. There isn't one specific path, except that I think you are going to definitely have to use the space at the very center of the room.
Game on,
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"
He who is certain he knows the ending of things when he is only beginning them is either extremely wise or extremely foolish; no matter which is true, he is certainly an
unhappy man, for he has put a knife in the heart of wonder."
-- Tad Williams