Ivan Fink is a researcher who allowed worms to grow in his body, testing them as a cure for asthma.
Ivan came into the hospital with pain, vomiting up worms. He was desperate for them to save the worms as he was researching them as a cure for asthma. The worms were known to release enzymes that help with allergies and he was applying the theory to asthma. The standard length of the experiment was a month or two, but he'd had the worms inside of him for 343 days, trying to grow them more to get more enzymes. He hadn't had an asthma attack in six months. The worms had caused a bowel obstruction, which required surgery. He wanted another option, so Bailey agreed to try an NG tube and fluids, but if he didn't improve, he'd have to have surgery. He didn't improve, so he was taken into surgery. He asked Cristina to try to save his worms because they were important to him. She tried, but she wasn't able to save them as his bowel had perforated and they had to suction the area. She also told him that for his safety, he needed to stop experimenting on himself, but he couldn't promise that.
Ivan is a biologist. He'd spent three years studying worms as a potential cure for asthma. He said he'd spent his life doing other people's experiments and now he was finally doing what he knew he was supposed to be doing.