The idea was to reach from inside the Pattern a place outside the Pattern. This was done by drilling a hole through that thinness in the Pattern (probably the thinness was already made by the DO), like a Gateway is made by men or TP users. This special "corridor/Gate" was called the Bore. It makes sense that it is a OP weave, if one can sense it.

That Unravelling is possible was unknown in the AoL. Probably the DO also blocked the Bore open once it was created, so one couldn't simply close the Bore.

I think it definitely makes sense that - if the Pattern made the Dragon the strongest and most able channeler on the world - that the OP will also somehow play a part in defeating the DO in the end. But we will see!