What does Gene mean when he admits that if anyone had been suspicious of what he had done to Finny he might have developed some defense of himself?

Had anyone accused Gene, he would have had to come up with a well thought out lie or confessed. It would have been easier for Gene because he wouldn't have spent so much time blaming himself and dealing with all of the guilty emotions alone. If anyone had accused him or been suspicious, he wouldn't have been able to keep silent and pretend nothing had happened on the outside, all while being consumed by guilt on the inside.