is there anything to do with the announcers?
His station had resumed its regular program. Four blocks beyond the zoo there was another break—the network was speculating that some members of the Presidential party, perhaps even President Kennedy himself, had been shot. Nothing was firm. Station routine was abandoned for a running account of developments in Dallas, but the announcer was being exceptionally guarded.】
does that mean the Liz group stopped? what does "but the announcer was being exceptionally guarded"mean?