That was actually recorded the night I was there! OMG - it was pretty embarrassing. I was all the way on the other side and heard the phone loud and clear. It just kept ringing and ringing. We were sinking in our chairs. I assume the person was too mortified to actually turn it off, thus revealing themself! Then a minute later, it rang AGAIN! This time while Daniel Craig was speaking. They both stayed in character, with their Chicago accents, but you could see it threw them for a loop. It was kind of funny, and kinda embarrassing.
Anyhoo - was the most "visually stunning" play I've been too . . . . and there was no set design.