Personally, I feel that Det. Hurst is REALLY trying to sell the theory that Brian definitely made it out of the building that night. At the start of this case it was "no other possible way Brian could have exited", now all of a sudden it's "there were a few exits he could have gone through". Also the cameras were a big focus, but now Hurst is saying to not focus on the cameras, as they were not reliable/working properly. I am in no way accusing him of anything sinister, but it just seems like he wants people to go with the idea that Brian can't possibly be in the construction zone. Seems like LE is doing anything to avoid being pressured into digging up the foundation, either because A) It's just simply a lot of work and resources that go into doing that and/or B) In the event that anything is found buried there, it could embarrass LE for a botched investigation.