I know this is probably off topic, but...
i missed finding out about Nina- she was an air purification machine...but thats all i know (since i lent someone my game and missed most of the plot). For some reason my game won't continue could anyone tell me what happened to her/why she went to the surface?

This was mentioned a while back about why the arm attacked Bosch.
The arm was made especially to help destroy a dragon or a person with a d-link. So the arm attacked Bosch directly after Chertyre linked with Bosch. This also explains why the arm goes nuts and seems to pull Bosch off of the side of the platform, Chertyre was behind the platform, the arm was pulling towards Chertyre.