I don't think the beaver line was all that far off the mark.
God asked Cain where his brother Abel was, KNOWING that Cain had killed him, just to see what he would say. Cain said, "Who am I, my brother's keeper?" Only THEN God sprang it on him. "Your brother's blood cries to me from the ground."
It is not out of character with God to do such things. Nor is it out of character with Lewis to portray God that way. Look at the Deep Magic discussion..... Aslan told the Witch, "Let us say that I have forgotten it. Tell me of this Deep Magic." He knew all about it. The witch practically screamed as much. "Tell YOU what was written on the world ash tree in letters deep as a spear??"
Aslan's point was the effect her words would have on the crowd. He wasn't too out-of-the-loop to know in advance who did what and why. He wanted her to say it out loud and implicate herself. He already knew what she was up to, he wanted everyone else to know he knew and that she knew what she knew.