Originally Posted by
Ironsmith
Adding to that case: Dvalin said he would obey the will of the clans. If the clan heads are being dominated, there's no way of knowing what their actual will is, and thanks to Gontor's blabbing, Dvalin knows that the vampires intend to dominate them. So either Dvalin takes a guess ("No! Are you freaking nuts?!") or delays voting as long as the vampires are a problem... and while the vote's unresolved, the world's not being destroyed.