The first thing you need to do is realize that it was 3:42 PM EDST in D.C. 9:42 is the time in Benghazi Libya which is six hours earlier than in D.C.
I think you meant later, as it was evening in Benghazi. There’s still 108 minutes of accounting for, as the attackers were unable to get in the Tactical Operations Center, so the agent in the TOC surely made that call at “the very beginning of this incident” as noted above from the SENIOR STATE DEPARTMENT OFFICIAL NUMBER ONE.