Harvey and Donna are talking in his office. Seen from behind him, his laptop screen is tilted towards him, from in front it is tilted away.
After Harry talked with Ester he goes to Rachel's office (at about the 22 minute mark). He begins talking with Rachel and two employees walk behind him past the door way. The camera cuts to Rachel, and then back to Harvey, and the same 2 employees walk by again in the same direction.
When Louis is attempting to listen through the wall, he holds the glass incorrectly. The open end collects the sounds and it picked up by the butt end of the glass.