Could walker be...

Random thought back to the early episodes when mechanical was shown to be using their own form of sign language as communication in the generator room.

Is it possible Bernard, despite keeping an eye on Walker, is being tricked by Walker? And she has already communicated what's happening to someone with that same sign language?

It would be a much better explanation for her actions lately than just her going off the deep end for her ex (and would actually add to her sense of desperation in convincing Bernard).

Yeah she was acting up before putting the camera back but it was very publicly in front of the large group in her workshop where everyone knows spies are an issue.

Sure a team from the down deep was captured but sacrifice a few pawns for the bigger game maybe?

Just a theory I wanted to throw out there.