A few things stood out for me. The first is that it wasn't the "47%" remark that ultimately caught his attention and got him concerned enough to think about important this tape was. What bothered him was Mr. Romney's story about visiting a horrific, oppressive factory in China that his company had bought, and how his takeaway from the experience was how well-run and good the experience was.
What was also interesting is all the questioning at the time (and subsequently) about Mr. Prouty doing a surreptitious, "undercover video." In fact, he noted that there had been no restriction on anyone bringing in recording devices to the event. No one was checked, and there even were people taking pictures and such all through the speech. There even was a Romney crew recording an official video. Amusingly, the only reason Mr. Prouty said he brought the camera was because he'd onced worked at an event where Bill Clinton spoke, and afterwards the former president came back to visit with the workers and took pictures with them all. Mr. Prouty thought that he should have a camera with him in case Mitt Romney did that, too.
My favorite thing in the long, and fascinating interview, though, was his reasoning for not making himself public when the tape came out. He said that it was because then he'd be the story, people would be writing about him, and the right wing media would be trying to tear him down -- and he wanted the focus entirely on Mitt Romney.
He came across as very informed and well-spoken, someone who was concerned enough that he did a lot of research before sending the videos out into the world.
He also said that the reason he's making himself public now is because Mitt Romney is making himself public and going around trying to whitewash his comments on his Fox News interview, blaming the media, blaming others and not taking any personal responsibility, and next speaking at CPAC.
I can't find the full broadcast, but here are two long segments. The first, the opening 16 minutes of the show, and the second, about six minutes when Scott Prouty is interviewed live in-studio with Ed Schultz.