I just googled a video of a replay of the experiment. It was... interesting, but I found my own reaction to it more interesting.

About halfway through, I started feeling cold and started to sweat at the same time. I found that I had unconsciously clenched my fists. Trying to relax did not work. About some time after that, I heard my teeth chattering. Then my heart started pounding madly. By the end of watching the experiment, I was absolutely tense, and I had finger-nail prints in the palms of my hands. I'm still shaking, for some reason. And it wasn't even me in the experiment; merely watching it did that to me.

I wonder what it would have been like for the actual subjects.