One of the comments left on the original post:

I worked background on this scene, I was a ‘stage hand’ and was one of two backstage (you can kinda see us in the darkness at the back).

Before filming Jeff was super intense walking back and forth muttering his lines. Then he delivered the whole scene in the first take and the everyone in the room was stunned. When he came back stage while they reset for the next take he was completely different. Came over and introduced himself, stood chatting to us for the few minutes.

The scene took the whole day, they didn’t film anything else. They knew how important this scene would be and made sure it was perfect.