Well if you want to know how the Dragon got taken down by Tamara this is a bit of a spoiler
[spoiler]her taser apparently is not a normal taser. Was looking at some other forums and some of the Once writers have said that it will be examined in a future episode. Speculation is that she has developed some type of anti-magic weapon.[/spoiler]
Which further leads to the question of who is Tamara? I think the two schools of thought are she is either a magical character who has been banished/had her magic taken away. Or she is someone who has suffered(or family) suffered due to magic and is now on the vendetta against it.