IGN interviewed Zack McGowan after Vane's death in 3X09. Because nobody really cares that Mr. Scott died an anticlimactic death after barely doing anything for two seasons.
* Zack says he always knew Vane was going to die, thought he would even die at the end of S1 or 2, just wanted to make sure he would die as the person he wanted him to be and not who he was introduced as. Just wanted to make sure he wouldn't plead for his life.
* Thinks Vane and Eleanor could have had a good albeit uninteresting life together, but Eleanor prioritized other things over their love. Zack loves that Eleanor beats up a chained, defenseless man and calls him an animal.
* Feels his death was greater than anything he could have done living. Says that Vane's death would be a strong pull to unite the people, but also that there were a lot of redcoats there and it wouldn't have been worth those men dying trying to rescue him.
* He loved exploring Vane's vulnerability with Teach and he tried to bring as much humanity to the character as he could.
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SOURCE 3X09 discussion post?