Did you ever hear the tragedy of Tuvix The Wise? I thought not. It’s not a story the Janeway would tell you. The dark side of transporter accidents are a pathway to many abilities some consider to be unnatural. He became so powerful… the only thing he was afraid of was losing himself, which eventually, of course, he did. Unfortunately, he taught Janeway everything he knew, then she killed him in a transporter cycle. Ironic. He could save others from death, but not himself.