Michael Frayn [the playwright] has used Margrethe brilliantly...
People are very opinionated as to what they think went on between Bohr and Heisenberg, and Frayn has used Margrethe as the voice of these different people at different times in the play. It comes through her. She really confronts Heisenberg... asking questions, voicing cynical attitudes and ideas.
You can't just wonder off in your mind... you follow the argument all the time.
Margrethe was known for being extremely courteous and polite. So it enables you to be able to sit there smiling, and listening to someone while your internal thoughts are being heard by the audience saying, you know, my god, this guy is an idiot.
And sometimes while you're just sitting there, not saying anything, you have to concentrate all the time because the other actors are relying on you to be very intensely concentrating.
There was a lot to do everyday, I think we've had 15 days shooting time which is very short.
But you click into it... the director keeps you and the set very focused. It's quite intense, but you haven't got people splitting off like particles -- now I'm getting into science terminology -- splitting off like particles into different areas.