Eric just wanted to take Silena with him and perhaps show Loki that she is alive, but according to Silena, the princess can't leave her time of duty on this vessel. She did say that once you swear, you stay, until Hades passes on, or until her one hundred years of servitude are over. He had a gut feeling that she could get hurt or punished if she helps him, but Eric wanted to leave. To show Loki that he was alive. He did hear his niece say something about a chest. "What do you know of this?", he asked on, just to get some answers.