If I were V's player, I'd be awfully tempted to dump my drink on the DM's notes and leave the game, as this reeks of just being one gigantic screw-job simply to feed the DM's ego.
"Oh look, here's this super-powerful dragon that's going to massacre everyone near and dear to you. And you can't do jack-all about it! Am I not clever?" *roll eyes*
*headdesk headdesk headdesk*
... okay, that feels better now.
While I would agree that such a turn of events might be disastrous for a player in a tabletop campaign and their trust of their DM, these are fictional characters who just happen to live by D&D rules. There are no players, there is no DM, and this has been repeated ad nauseum both here and on the OotS forums (I tried to find the relevant discussion on the GitP boards so I could link it, but I'm tired and my forum-fu is weak).
Also, I've been in campaigns where turns of events like this happened and were okay with the group. The key here is, was it dramatically appropriate and did the character bring it on themselves? I say yes to both in V's case; V has repeatedly ignored moral and story dilemnas by simply not bothering to be concerned about them. (S)he is completely emotionally detached; as a DM, I'd be kind of sick of it by now and would find what
does emotionally rope in the character so that he doesn't feel quite so much like a cookie-cutter power-hungry mage. In addition, V may have been able to put up a fight with the dragon or at least stop her progress... but (s)he's been abusing the rest and recovery rules in order to munchkin his/her magic. As such, his/her inability to keep the dragon from leaving to attack those (s)he cares for? His/her own fault entirely.
And, yes, I realize that through this rant I prove myself biased against mercenary characters. Other people may like their PCs/fantasy protagonists to be detached and unshakeable, and that's fine in their games, books, or cinema. Personally, I like my PCs and fictional heroes to be driven by something a bit more personal. Even the neutral ones.
As always, your casting range may vary.