Why didn't Durkon Plane Shift to Celestia to talk to Roy?

[One Step Two]

"Precise accuracy as to a particular arrival location on the intended plane is nigh impossible. From the Material Plane, you can reach any other plane, though you appear 5 to 500 miles (5d%) from your intended destination" and Durkon didn't even really know where exactly his intended destination was? Celestia's bound to be huge.

This is also the same issue when you Plane Shift back, especially when your return point is somewhere in the ocean. And you're wearing plate armor.