Thanks for finding this, was it linked in the article and I just missed it?

Either way, I was wondering if people shocked themselves out of curiosity, but the part after what you quoted says "Note that these results only include participants who had reported that they would pay to avoid being shocked again... But what is striking is that simply being alone with their own thoughts for 15 min was apparently so aversive that it drove many participants to self-administer an electric shock that they had earlier said they would pay to avoid." They all already knew what it would feel like and they did it anyway.