Some symbolism, the archway he is facing out of the archway signifying he is in the know. The shadows and lighting, the shadow is to his left (the left is in the dark, the right is lighted) ...Dark to light and the light is greater than the dark. He is doing no hand gestures therefore not rehearsed. I say that because when he rehearses, he does specific gestures to make key points and remember where he is in the speech.
I may be wrong and all of this is coincidence, but I try ....