[aprescott]

I believe it's been shown in video feeds that Lee Sedol had left the room before move 37. He came back from a smoke break and noticed AlphaGo's shoulder hit play. It's of course still dramatic when he comes back and sees it. You can see some discussion about it at https://www.reddit.com/r/baduk/comments/49zik4/the_sadness_a... and the moment in video at https://youtu.be/VunLUhNP_Aw?t=2590