Sorry, PhychoMom . . . With all respect for your professional opinion about SMD's demeanor on camera, I think you are neglecting to consider one of the most important questions here. WHY is he doing the interview at all?
How many of LG's law school friends, including those who looked for her Wed. night and went to the MPD with SMD on Thursday, consented to an interview? Zero. Why is that?
Several reasons: they are personally upset about the disappearance of their friend LG; and (later) even more upset about her death; and they consider this a personal loss. They want to be with and talk with their friends who knew LG, not to communicate with the public or explain things to a pushy reporter who did not know LG and is acting in a manner most of us would find offensive, wanting to record video of either anguish, maudlin sentimentality, or shock. Surely people don't want to display themselves to others at a time such as this.
After the friends are informed that LG has been killed, they realize that a crime has been committed and desire to cooperate fully with LE, but would think that media questions to them at this time are both intrusive and likely to not assist LE in solving the crime and arresting the perpetrator.
SMD, on the other hand, is moved to give all sorts of information in extreme detail. That is a defensible action, especially when he thinks LG is missing, but after he learns a body has been found, I think it indicates that he is making a terribly bad decision to attempt to sell the media on the alternative theories (snatched while running; hoodlums; BF) that he has thought through so many times in the past 5 days. He has rehearsed these facts and he wants to publish them, hence the continued interview after he regains his composure and returns from the ATT building.
He even remembers the name of the detective whose car in in front of the apts. He has been paying acute attention to all the details of the investigation, more than I think is normal.
More than anything else, though, the fact that he goes on camera repeatedly tells me he has a reason other than concern for Lauren Giddings.