The whole set-up of this was really weird and lame. It made the White Walker army look pretty pathetic just standing around and staring. Not one of them had a ranged weapon? Oh wait the King guy had an icicle spear he didn't bother to use until the dragons came. They weren't even paying attention to the ice freezing over. Who knows how long they were waiting for no reason.
The set-up would have worked better if they were hiding behind enemy lines barely surviving or something.
Like another poster earlier said, the only way that scene made any sense is if the night king knew dany would come (somehow) so he can use a dragon
if it's not that, honestly the writers are just lost at this point and don't care about making sense
if you watch the "Inside the Episode" featurette that HBO Now plays after the episode, pretty much all Dan Weiss talks about is how they knew certain plot points that they wanted to have happen (mainly capturing the wight, the party getting stranded, and Dany rescuing them) and everything else was kinda sorta fill in the blanks here, connect these lines there, in ways that could happen or could make some kinda sense. it was pretty laughable watching him explain their process and all actually.
