Even before he was arrested and tried for the disgusting, horrific attack on Frank and Alice Longbottom, Rodolphus was already regretting making the decision to become a Death Eater. Unlike his younger brother who was a loyal fanatic, he'd only initially joined because he saw the opportunity to get up the skirt of a pretty witch. By the time he knew exactly what he'd gotten himself into, it was too late to get out. He did what was necessary to survive, telling very few people about his hidden talent.