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

[Fyraltari]

I was reading some old strips when I came upon this one and thought, if the evil adventuring party can Plane Shift to Celestia, why couldn't Durkon? We know he has that spell and Roy could have helped him coordinate meeting back up with Haley and Belkar.

Obviously this would have spoiled a major narrative arc, but are there any practical reasons why this would not have worked?

A) Durkon at that time was extremely passive and rarely took any initiative.

B) Celestia is a near infinite plane. Once he'd plane shifted there, could he find Roy?

C) Living people don't really seem to be allowed on the premises. Durkon, as a deeply religious and lawful man, would not want to disturb the workings of the afterlife and the authorities would escort him out.