So this scene was deleted from the finale. I think it just serves as proof of how shit and rushed the script was.
"We actually did a scene that clearly got cut, a short scene with Sansa where she knocks on Bran’s door and says, “I need your help,” or something along those lines. So basically, as far as I know, the story was that it suddenly occurred to Sansa that she had a huge CCTV department at her discretion and it might be a good idea to check with him first before she guts her own sister. So she goes to Bran, and Bran tells her everything she needs to know, and she’s like, “Oh, s—.”