"It's not your fault."
"Long story short, Tom was kicked out of Starfleet after covering up a piloting error that led to the death of 3 crew members. He confessed shortly after out of guilt, but obviously Starfleet didn't find that convincing. He joined the Maquis, got caught basically immediately, and was sent to prison. The captain offered him his freedom in return for helping track down the Maquis."
"After Voyager was abducted, he acted heroically to save myself and two other members of the crew. The captain restored his commission."
"Tom has had to tell this story many many times, and I think he just couldn't stand to tell it another time."