For fuck sakes, let the poison thing go. Showing any build up of how she got it would have completely destroyed the surprise of her eliminating them all in one clean stroke.
Anywho, I am curious how the walkers are going to get past the wall. Did Bran fuck up somehow by crossing the wall? They just going to walk around?
Also, I think they meant to show that one giant walker and have us think Wun Wun because it's the one we could relate to. But it was more for the message of ya we raise these fuckers too.