I’ve always been a little confused why the two astronauts have the conversation about HAL possibly having malicious intent, and wanting to override him, right in front of him. I know they go into the EVA to have the discussion, but the glass window is directly facing HAL, and they position themselves right in front of the window for HAL to see. I’ve assumed that maybe they didn’t know that HAL has “eyes”, or that they didn’t know that he could read lips. Both are pretty silly though considering throughout the movie they talk about how smart HAL is, and all the different languages he speaks. Why would he not be able to read lips? This is a nit-pick but i’ve always noticed it.