Well
So the scene was ultimately a failure, but at the time it made sense for Walt to try and hide from Raiku behind the fascade.
Effectively we were seeing what Raiku and Grace were seeing, and Walt was hoping that Raiku wasn't good enough to see through it. But after he spoke with her later he confirmed that she was and the had to kill her.But...
... that only makes sense if the entire wind-up was purely for us, the audience, since I don't think that the conversation before Raiku did a deep dive, also, supports that she was aware of what was going on. Sad to see that Anna will only have the one appearance. I liked her character.
So the scene was ultimately a failure, but at the time it made sense for Walt to try and hide from Raiku behind the fascade.