Probably doing security recon for Huber's people. Also there was 18mil in the omnibus bill for "witness protection" so I wouldn't be surprised if they are using military protection for said witnesses.
This is also a lie. Brennan claimed that he didn't see the dossier before 12/16 and claimed it was "widely known to the media". However, we have evidence that they applied and failed for FISA warrants before this… Nellie Oher is the key