re: GoT "Middle Ground" Thread - Between Seasons Edition ***Spoilers Possible***

That one WW didn't know what to think about Jon's Valyrian steel, so I don't think they know enough to know they can be hurt (thus even if they did know there was a bag of dragon glass, they didn't know it was deadly to them).

I think the timing happened because they saw all the empty boats show up. They can't very well command a massive army of dead wildlings if there aren't any dead wildlings around. So they see a shitload gathered together and that's okay. But when the boats show up and they start heading out to those boats, the WW's knew they had to act immediately.