After what happened to him, Rurik needed to learn how to live with his new self. He needed to learn how to accept that emptiness inside him.
He could very well try to kill himself, but he couldn't. All the times when he tried to take his artificial life, he would fail. The Indigo Energy inside him prevented him to do so. Also, the scientists and healers that worked on Project Draugr didn't let him go any further on that suicidal thing.
No matter how many different ways that Rurik used to try to die again, he couldn't do it. He filled his body with gunshots, drunk poison, set fire on himself, and even reduced his body to dust with a certain weapon, but it would always recover from the most impossible wounds and diseases.
He never got sick, even though many times he exposed himself intentionally to make it happen. He could starve, run out of oxygen, and even get his brain and heart separated from his body.