By the way, another question.
It is said vampires can't be killed unless killed by fire *or werevolves* and just like that werevoles can be killed by fire *or vampires*. 
How exactly does that work? Does that mean that a vampire can be killed by teeth of a werewolf's wolf form and in turn can kill a werewolf with his fangs? Or does that mean that if for example a werewolf beats a vampire with a sword it suddenly becomes lethal to him because it is held by a werewolf?