To wish someone good riddance is to be pleased that they are leaving, and in this context he is pleased that he will never have to see that person again.
Consider the staetement "He pushed himself through the rift without so much as a goodbye, or even a pleased feeling that he would never have to see that person again.". Based on this statement, is "He pushed himself through the rift without so much as a goodbye, or even a good riddance." a true statement? Yes/no/unknown