dr. sherry wren: i think it's really easy for him to say that. he's not the guy doing it. >> cooper: dr. sherry wren is a vice chair of surgery at stanford university school of medicine. >> wren: the bottom line is, is he going to stand there and volunteer to let me paint some hepatitis c blood on his arms and on his stomach? probably not is going to be my guess. >> cooper: and you've had hepatitis c blood on your arms and on your stomach? >> wren: of course. >> cooper: dr. wren specializes in gastro-intestinal surgery, and is co-author of guidelines for surgeons operating on patients with ebola. she has no connection to the lawsuit against halyard, but she does wear microcool gowns for procedures like this one, in which she knew the person she was operating on had hepatitis c. shortly after we recorded this surgery, dr. wren told us she got blood on her arms and hands three times, while wearing three different microcool gowns and operating on another patient who also had hepatitis c. we've been told that as long as your skin is intact, you're oka