In the episode Nelson v Murdock (S01E10), Karen comes into the office to find Ben waiting for her. Ben says that he found the door unlocked.
As they discuss this, the camera perspective cuts to a shot from inside Matt's office, looking at Karen. The camera shakes a bit as though it's a first person POV.
No mention of this is made again in any way that I can recall, but given previous events, a break-in in the office would not be unrealistic.
Did someone break into the office, or did Karen really just forget to lock the door? Is there any evidence (interview, etc) that this was a remnant of a dropped plot line?