I don't understand why you think there are too many assumptions - Edit 1
Before modification by darius_sedai at 02/12/2009 05:38:33 PM
Distance attenuates the Bond, and I have to imagine that being in a different dimension with a different set of rules of time and space caused whatever connections she had to Randworld to be broken.
In Tear she went to Finnland and the bond survived just fine. We've also seen when Rand travled people via the portal stone in TGS (including Verin) that the warder bonds survived just fine.
The only difference is that the doorway melted in this instance. I believe it takes way too many assumptions to ascert that the doorway melting could break the bond (or that even being in another dimension could).
For certain we know of two ways that Warder bonds go away - death and stilling/burning out. We know she's alive, so that leaves stilling/burning out.
It is remotely possible that Moiraine released the Warder bond herself as she fell into the doorway. But that seems like it'd be way too much concentration for someone who wrestling with a fosaken who is much, much strong and has an angreal.
It's more simplistic than her connection to saidar being severed. Basically she walked through a door with her bond on one side her on the other. The door slammed shut permanently. Bond severed. simple enough.
Her previous trip the door didn't close on her so of course the Bond stayed in place.