From the NYTimes article:
"As midnight approached, I was writing away in my room at the Kempinski Hotel in West Berlin when there came a knock on the door. It was Victor Homola, my translator from East Berlin.
“I’m busy, Victor,” I snapped.
“Not now! Not now…”
Wait! Victor was an East German. He was not allowed to cross into the West! He’d never been to the West! And it was midnight.
“Victor, what on earth are you doing here?”
“That’s what I’m trying to tell you, Serge. The wall is open!”